Every descriptor, with its units

All 164 descriptors tcren features --all emits, in catalogue order, with what each is invariant under and what it is measured in. The receptor column says whether the TCR enters the definition: a column marked no is computed from the peptide and its allele alone, so every structure of one epitope on one allele shares its value whatever the receptor, and it carries cohort identity rather than interface physics.

Units are what a transform has to respect. A count is variance-stabilized by a square root, a fraction by the arcsine – the classical angular transformation – and an unbounded continuous quantity by neither.

placement (31)

Where the receptor sits on the groove and how it leans. Every column is a length, an angle or a direction cosine, so the family is geometric throughout.

descriptor	invariance	units	receptor	definition
pitch	geometric	deg	yes	Incident angle of the TCR out of the groove plane. Banned as a feature: it reproduces no clean geometric angle yet out-discriminates every one of them, which is AlphaFold-confidence contamination rather than geometry.
crossing	geometric	deg	yes	Crossing (scanning) angle between the Valpha->Vbeta axis projected into the groove plane and the groove long axis.
crossing_signed	geometric	deg	yes	The same angle on [-180, 180); its sign is the docking polarity, canonical or reversed.
dock_d	geometric	A	yes	MHC-stub to TCR-stub rigid-body separation.
dock_torsion	geometric	rad	yes	Rigid-body dihedral of the TCR about the MHC stub; the docking twist. Circular, wraps at +-pi.
dock_tcr_uy	geometric	cosine	yes	y component of the TCR stub unit vector in the MHC frame.
dock_tcr_uz	geometric	cosine	yes	z component of the TCR stub unit vector; how high the receptor body rides over the groove.
dock_mhc_uy	geometric	cosine	yes	y component of the MHC stub unit vector.
dock_mhc_uz	geometric	cosine	yes	z component of the MHC stub unit vector.
height	geometric	A	yes	Elevation of the CDR Calpha centroid above the groove plane.
shift_u	geometric	A	yes	In-plane displacement of that centroid from the peptide centroid along the groove long axis.
shift_w	geometric	A	yes	The same along the groove short axis.
offset	geometric	A	yes	Length of the in-plane displacement; lateral shift whatever its direction.
cdr3a_reach	geometric	A	yes	Distance from the loop’s Calpha centroid to the peptide Calpha centroid; how far CDR3alpha reaches.
cdr3a_ou	geometric	cosine	yes	Where CDR3alpha sits over the groove, along the long axis u.
cdr3a_ow	geometric	cosine	yes	Where CDR3alpha sits over the groove, along the short axis w.
cdr3a_on	geometric	cosine	yes	Where CDR3alpha sits over the groove, along the groove normal n.
cdr3a_au	geometric	cosine	yes	Orientation of CDR3alpha’s N->C axis against the groove long axis u.
cdr3a_aw	geometric	cosine	yes	Orientation of CDR3alpha’s N->C axis against the groove short axis w.
cdr3a_an	geometric	cosine	yes	Orientation of CDR3alpha’s N->C axis against the groove normal n.
cdr3a_topep	geometric	A	yes	Minimum Calpha-Calpha distance from CDR3alpha to the peptide; its engagement depth.
cdr3a_ext	geometric	A	yes	End-to-end extension of CDR3alpha, the Calpha_N to Calpha_C distance.
cdr3b_reach	geometric	A	yes	Distance from the loop’s Calpha centroid to the peptide Calpha centroid; how far CDR3beta reaches.
cdr3b_ou	geometric	cosine	yes	Where CDR3beta sits over the groove, along the long axis u.
cdr3b_ow	geometric	cosine	yes	Where CDR3beta sits over the groove, along the short axis w.
cdr3b_on	geometric	cosine	yes	Where CDR3beta sits over the groove, along the groove normal n.
cdr3b_au	geometric	cosine	yes	Orientation of CDR3beta’s N->C axis against the groove long axis u.
cdr3b_aw	geometric	cosine	yes	Orientation of CDR3beta’s N->C axis against the groove short axis w.
cdr3b_an	geometric	cosine	yes	Orientation of CDR3beta’s N->C axis against the groove normal n.
cdr3b_topep	geometric	A	yes	Minimum Calpha-Calpha distance from CDR3beta to the peptide; its engagement depth.
cdr3b_ext	geometric	A	yes	End-to-end extension of CDR3beta, the Calpha_N to Calpha_C distance.

interface (26)

How much contact there is and of what chemical kind. Two continuous quantities – buried surface and clash depth – and counts for the rest.

descriptor	invariance	units	receptor	definition
burial	geometric	A^2	yes	Interface buried surface, SASA(TCR) + SASA(pMHC) - SASA(complex), by Shrake-Rupley.
extent	compositional	count	yes	Distinct TCR residues contacting the pMHC over both receptor interfaces.
chain_balance	compositional	fraction	yes	min(a,b)/(a+b) over TCR:peptide contacts by chain; 0.5 when both chains engage equally, 0 when only one does.
n_contacts_tp	compositional	count	yes	TCR-peptide residue-residue contacts.
n_contacts_tm	compositional	count	yes	TCR-MHC residue-residue contacts.
n_pep_contacted	compositional	count	yes	Distinct peptide residues the TCR contacts.
n_hbond	compositional	count	yes	Polar N/O atom pairs within 3.5 A across TCR:peptide.
ct_tp_salt_bridge	compositional	count	yes	Cationic-N / anionic-O pairs within 4 A across TCR:peptide.
ct_tp_aromatic	compositional	count	yes	Ring-atom pairs between aromatic residues across TCR:peptide.
ct_tp_hydrophobic	compositional	count	yes	Apolar C-C pairs between apolar residues across TCR:peptide.
ct_tp_other	compositional	count	yes	Remaining classified TCR:peptide contacts.
ct_tm_salt_bridge	compositional	count	yes	Salt bridges across TCR:MHC.
ct_tm_hydrogen_bond	compositional	count	yes	Hydrogen bonds across TCR:MHC.
ct_tm_aromatic	compositional	count	yes	Aromatic contacts across TCR:MHC.
ct_tm_hydrophobic	compositional	count	yes	Hydrophobic contacts across TCR:MHC.
ct_tm_other	compositional	count	yes	Remaining classified TCR:MHC contacts.
cdr3_dominance	compositional	fraction	yes	CDR3(alpha+beta) share of all CDR TCR:peptide contacts.
cdr3_ab_imbalance	compositional	fraction	yes	abs(CDR3a - CDR3b) / (CDR3a + CDR3b); how one-sided the CDR3 engagement is.
chain_cdr_imbalance	compositional	fraction	yes	abs(a - b) / (a + b) over all CDR contacts; the chain-level mirror of chain_balance.
n_clashes	compositional	count	yes	Peptide-partner heavy-atom pairs overlapping by more than 0.4 A on Bondi radii.
clash_score	geometric	A	yes	Summed overlap depth of those clashing pairs; the steric burden of a forced pose.
mhc_class_bin	categorical	class I / II	no	Which class of MHC presents the peptide: 0 for class I, 1 for class II. Class I and class II grooves differ in shape and in how they hold a peptide, so this conditions the other descriptors rather than being scored beside them; a coefficient fitted across both classes without it is fitted to a mixture.
n_loop_contacts	compositional	count	yes	Contacts the six-CDR-loop partition sees; framework contacts are outside it by construction.
n_pep_contacts	compositional	count	yes	Of those loop contacts, the ones reaching the peptide.
n_mhc_contacts	compositional	count	yes	Of those loop contacts, the ones reaching the MHC.
n_pep_int	compositional	count	no	Intra-peptide residue contacts, at 5 A with a sequence separation of at least three.

topology (70)

The footprint: its connectivity, its composition over labelled cells, and how the receptor’s contacts spread along the peptide.

descriptor	invariance	units	receptor	definition
H_cell	compositional	fraction	yes	Normalized Shannon entropy of the contact composition over the twelve cells (six CDR loops x {peptide, MHC}).
D1_cell	compositional	count	yes	Hill number of order 1 over the same cells, exp(H); monotone in H_cell.
D2_cell	compositional	count	yes	Hill number of order 2, 1/sum(p^2); the effective number of engaged cells, discounting the weakly populated ones.
S_cell	compositional	count	yes	Richness: how many of the twelve cells are occupied.
J_cell	compositional	fraction	yes	Pielou evenness over the occupied cells. NaN when one cell is occupied.
H_loop	compositional	fraction	yes	Normalized entropy over the six CDR loops alone, ignoring which target each contact reaches.
D2_loop	compositional	count	yes	Hill number of order 2 over the six loops.
D2_pep24	compositional	count	yes	Hill number of order 2 over the twenty-four-cell partition, the peptide split into N-terminal, central and C-terminal bands.
ab_imb	compositional	signed fraction	yes	Signed (TRA - TRB)/(TRA + TRB) over CDR-loop contacts; positive is alpha-shifted.
ab_imb_pep	compositional	signed fraction	yes	The same restricted to peptide-side contacts.
ab_imb_mhc	compositional	signed fraction	yes	The same restricted to MHC-side contacts.
L_canon	compositional	log-odds	yes	Canonical-docking log odds-ratio of loop class (germline, CDR3) against target (MHC, peptide), Haldane-Anscombe corrected. High when CDR3 sits on the peptide and the germline loops on the helices.
p_germ_mhc	compositional	fraction	yes	Share of germline (CDR1/CDR2) contacts that reach the MHC.
p_cdr3_pep	compositional	fraction	yes	Share of CDR3 contacts that reach the peptide.
pep_free_frac	compositional	fraction	yes	Share of the peptide the groove leaves for the receptor: mean over positions of n_TCR/(n_TCR + n_MHC). The threshold-free reading of ‘peptide without its MHC anchors’.
pep_cov_frac	compositional	fraction	yes	Peptide positions the TCR contacts, over peptide length.
pep_cov_even	compositional	fraction	yes	Pielou evenness of the accessibility-discounted contact distribution, base ln(peptide length); how evenly the receptor uses the peptide it can reach.
pep_cov_d2n	compositional	fraction	yes	Hill number of order 2 of that distribution over peptide length; the effective share of the peptide engaged.
pep_cov_centre	compositional	fraction	yes	Contact-weighted mean position on [0, 1] from N- to C-terminus; 0.5 is centred.
pep_cov_spread	compositional	fraction	yes	Contact-weighted standard deviation of that position, doubled; approaches 1 when the receptor reaches both termini.
h0_pers_ent	geometric	fraction	yes	Normalized entropy of the H0 barcode of the contacted pMHC Calpha cloud. The bar lengths are the minimum spanning tree’s edges, so no filtration is chosen.
g_even_tcr	topological	fraction	yes	Pielou evenness of the contact degrees of the engaged CDR-loop residues, base the engaged count. 1 when every engaged residue carries the same number of partners.
g_even_pmhc	topological	fraction	yes	Pielou evenness of the contact degrees of the engaged pMHC residues, base the engaged count.
g_comp_frac	topological	fraction	yes	Connected components of the bipartite contact graph per node; the parameter-free form of the footprint patch count, needing no Calpha radius.
g_alg_conn	topological	ratio	yes	Second-smallest eigenvalue of the normalised Laplacian on the largest contact-graph component, in [0, 2]. Near 0 when the footprint is about to fall into two patches.
g_cyclo_frac	topological	fraction	yes	Contacts beyond a spanning forest over all contacts, (E - V + C) / E, which is the contact graph’s first Betti number made size-free. High when the footprint is interlocked.
g_loop_even	compositional	fraction	yes	Pielou evenness over the six CDR loops of the number of distinct pMHC residues each reaches, base 6. Counts partners rather than contacts, so it does not track residue size.
g_loop_overlap	compositional	fraction	yes	Mean pairwise Jaccard overlap of the engaged CDR loops’ pMHC partner sets. High when the loops crowd onto the same residues instead of partitioning the surface.
g_assort	topological	ratio	yes	Degree assortativity of the contact graph: the correlation, over contacts, between the degrees of the two residues involved.
degree_evenness_tp	compositional	fraction	yes	Participation ratio of the receptor-side contact degrees across TCR:peptide, in [0, 1]. Low when a few over-reaching side chains hoard the contact budget.
frac_well_coordinated_tp	compositional	fraction	yes	Share of contacting receptor residues reaching no more than three peptide residues, the count a crystal side chain typically makes.
m_erank_tp	geometric	fraction	yes	Effective rank of the CDR-loop x peptide Calpha proximity kernel over its maximum: how many independent approach modes the interface has. Peptide-length coupled (Spearman -0.547 on 148 class I crystals) because a longer class I peptide bulges.
m_gap_tp	geometric	ratio	yes	Second over first singular value of that kernel. Near 0 when the approach is separable into a loop profile times a peptide profile rather than pairing specific residues.
m_erank_tm	geometric	fraction	yes	Effective rank fraction of the CDR-loop x MHC-helix kernel. CDR3-length coupled (Spearman -0.437), so it reads how much loop there is to spread over the helices.
m_gap_tm	geometric	ratio	yes	Second over first singular value of the CDR-loop x MHC-helix kernel. The least length-coupled column in the catalogue: -0.012 against CDR3 length, +0.027 against peptide length, 99.9 per cent of its variance surviving both.
m_face_tp	geometric	A	yes	Mean Calpha-Calpha minus Cbeta-Cbeta distance over the contacting TCR:peptide residue pairs. Positive when side chains lean towards each other, negative when the backbones are the close part and the side chains point away.
m_face_tm	geometric	A	yes	Mean Calpha-Calpha minus Cbeta-Cbeta distance over the contacting TCR:MHC residue pairs.
ca_cb_agreement_tp	geometric	ratio	yes	Spearman correlation between the Calpha and Cbeta distance maps over the TCR:peptide approach shell. High when the side chains track the backbone, as they do in a crystal.
ca_cb_agreement_tm	geometric	ratio	yes	The same rank correlation across the TCR:MHC approach shell.
fp_b0_r7	topological	count	yes	Betti-0 of the flag complex on the contacted pMHC Calpha atoms at 7 A: how many disconnected patches the footprint falls into.
fp_b1_r7	topological	count	yes	Betti-1 at 7 A: how many holes the footprint encloses.
fp_chi_r7	topological	count	yes	Euler characteristic b0 - b1 at 7 A.
fp_b0_frac_r7	topological	fraction	yes	Patches per contacted residue at 7 A; the size-free form of Betti-0.
fp_b0_r8	topological	count	yes	Betti-0 of the flag complex on the contacted pMHC Calpha atoms at 8 A: how many disconnected patches the footprint falls into.
fp_b1_r8	topological	count	yes	Betti-1 at 8 A: how many holes the footprint encloses.
fp_chi_r8	topological	count	yes	Euler characteristic b0 - b1 at 8 A.
fp_b0_frac_r8	topological	fraction	yes	Patches per contacted residue at 8 A; the size-free form of Betti-0.
sc_shape	geometric	ratio	yes	Pearson r between the pMHC and TCR height fields over the shared grid; positive is complementary, the receptor riding up where the groove rises. Lawrence & Colman’s Sc is the same idea on a dot surface.
sc_charge	compositional	ratio	yes	Pearson r between the two charge fields; NEGATIVE is complementary, plus meeting minus.
sc_phobic	compositional	ratio	yes	Pearson r between the two Kyte-Doolittle fields; positive is complementary, apolar meeting apolar.
sc_charge_prod	compositional	ratio	yes	Mean per-cell product of the two charge fields.
sc_phobic_prod	compositional	ratio	yes	Mean per-cell product of the two hydropathy fields.
sc_gap_mean	geometric	A	yes	Mean of h(TCR) - h(pMHC) over retained cells. Negative on a real interface: the median cell interdigitates.
sc_gap_sd	geometric	A	yes	Spread of the same gap. High when the receptor rests on a few high points rather than meshing.
sc_gap_vol	geometric	A^3	yes	Void volume, the gap integrated over the contact plane where it is positive.
sc_interlock	geometric	A^3	yes	Interdigitated volume, the gap integrated where it is negative. The larger of the two on a real interface.
sc_gap_index	geometric	A	yes	Void volume over retained contact area; the intensive form of the gap-volume channel.
sc_interlock_frac	geometric	fraction	yes	Share of retained cells whose gap is negative; the per-structure form of the corpus 71% interdigitation.
sc_gap_depth	geometric	A	yes	Mean depth over the interlocked cells alone: how far the receptor reaches in where it does.
sc_gap_height	geometric	A	yes	Mean standoff over the void cells alone: how high it stands where it does not mesh.
sc_gap_asym	geometric	signed fraction	yes	(void - interlock) / (void + interlock); -1 for a face that only interlocks, +1 for one that only stands off.
sc_dh	geometric	A	yes	Mean absolute per-cell height difference between the two faces.
sc_dcharge	compositional	ratio	yes	Mean absolute per-cell charge difference between the two faces.
sc_dphobic	compositional	ratio	yes	Mean absolute per-cell hydropathy difference between the two faces.
sc_cells	geometric	count	yes	Grid cells entering the comparison; bookkeeping, so a low complementarity can be told from a thin one.
sc_coverage	geometric	fraction	yes	Retained cells as a share of the occupied pMHC cells in the window; bookkeeping.
co_pep	compositional	ratio	yes	Contact order on the peptide: mean sequence separation of the peptide residues one CDR loop reaches, averaged over loops and divided by the peptide’s span.
co_mhc	compositional	ratio	yes	Contact order on the MHC helices, by the same construction.
partcoef_tcr	compositional	fraction	yes	Mean over engaged TCR residues of 1 - sum_s (k_s/k)^2 with the modules peptide and MHC; 0 when every residue reads one target only.
partcoef_pmhc	compositional	fraction	yes	The same over engaged pMHC residues with the six CDR loops as modules.

energetics (15)

Statistical-potential interface sums and their poly-alanine references. Lower is more favourable.

descriptor	invariance	units	receptor	definition
Phi_tcr_pep	energetic	log-odds	yes	Phi over TCR-peptide contacts under TCRen2, summed over all TCR regions. Lower is more favourable.
Phi_tcr_mhc	energetic	log-odds	yes	Phi over TCR-MHC contacts under Miyazawa-Jernigan.
Phi_cdr12	energetic	log-odds	yes	The CDR1 + CDR2 part of the TCR:peptide energy, both chains.
Phi_cdr3a	energetic	log-odds	yes	The CDR3alpha part of the TCR:peptide energy.
Phi_cdr3b	energetic	log-odds	yes	The CDR3beta part of the TCR:peptide energy.
dPhi_tcr_pep	energetic	log-odds	yes	Poly-alanine reference delta of the TCR:peptide energy; the pose-geometry baseline removed.
dPhi_pep_soft	energetic	log-odds	yes	Smoothed reference delta, peptide direction: the peptide’s energy minus the free energy of the residue background at each peptide position, receptor frozen.
varPhi_pep_soft	energetic	log-odds^2	yes	Variance of the local field under the background, peptide direction: how sharply each peptide position’s energy responds to residue identity, summed over positions. NOT a ddG – it is a second cumulant, not a difference of differences.
dPhi_tcr_soft	energetic	log-odds	yes	Smoothed reference delta, receptor direction: the receptor’s energy minus the free energy of the residue background at each contacted TCR position, peptide frozen.
varPhi_tcr_soft	energetic	log-odds^2	yes	Variance of the local field under the background, receptor direction, summed over contacted TCR positions.
dPhi_tra_soft	energetic	log-odds	yes	The alpha-chain part of the receptor-direction smoothed reference delta.
dPhi_trb_soft	energetic	log-odds	yes	The beta-chain part of the receptor-direction smoothed reference delta.
Phi_pep_mhc	energetic	log-odds	no	Phi over peptide-MHC contacts under Miyazawa-Jernigan. Computed without the receptor.
dPhi_pep_mhc	energetic	log-odds	no	The same reference across peptide:MHC. Computed without the receptor.
Phi_pep_int	energetic	log-odds	no	The peptide’s own intra-chain contact energy. Computed without the receptor.

potts (5)

The same interface read against the partition function of the coupled contact model rather than against a poly-alanine interface.

descriptor	invariance	units	receptor	definition
neg_energy	energetic	kT	yes	-E of the observed contact map under the coupled Potts model; higher is more native-like. Exactly log_z + log_lik.
log_z	energetic	kT	yes	Log partition function over every contact map the geometry admits; the interface’s capacity.
log_lik	energetic	kT	yes	Log probability of the observed contact map; its typicality.
psi	energetic	kT/site	yes	log_lik per available site, so interfaces of different size compare.
n_contacts	energetic	count	yes	Available residue pairs that engaged. Distinct from the footprint’s loop tally.

kinetics (17)

The contact map as a network of breakable springs. No potential enters: these are geometry and multiplicity, which is why they carry evidence the energies cannot.

descriptor	invariance	units	receptor	definition
exp_lost	geometric	count	yes	Expected TCR:peptide contacts lost under a 1 A isotropic shift.
mean_margin	geometric	A	yes	Mean contact margin, cutoff minus minimum heavy-atom distance.
frac_robust	compositional	fraction	yes	Share of TCR:peptide contacts with at least 1 A of margin.
K_tens	geometric	N/m	yes	Tensile stiffness along the docking axis.
K_shear	geometric	N/m	yes	In-plane stiffness, S_tot minus K_tens.
aniso	geometric	ratio	yes	K_shear / K_tens; how much stiffer the interface is along the pull than across it.
lam_max	geometric	N/m	yes	Largest eigenvalue of the stiffness tensor.
lam_min	geometric	N/m	yes	Smallest eigenvalue of the stiffness tensor.
n_spring	compositional	count	yes	Springs in the interface network; every other kinetics column is NaN below three.
S_tot	geometric	N/m	yes	Trace of the stiffness tensor; total interface stiffness.
rupture_force	geometric	N	yes	Peak resisting force under steered separation along the weaker axis.
rupture_work	geometric	J	yes	Force integrated to full separation; the off-rate proxy, and a geometry-only quantity no potential enters.
couple_pep	compositional	count	yes	Peptide residues contacting both the MHC and the TCR.
couple_mhc	compositional	count	yes	MHC residues contacting both the peptide and the TCR.
couple_tcr	compositional	count	yes	TCR residues in the Valpha-Vbeta interface that also contact the pMHC.
couple_total	compositional	count	yes	Sum of the three coupling counts.
n_interface	compositional	count	yes	Interface residue count; the size denominator for the coupling counts.

flagged descriptors (33)

Descriptors that need a second look before they are used, from tcren.recognition.STATUS. A name absent from this table has no known defect; presence is not a reason to drop the column, only to know what it is. suspicious means the quantity is not measuring what its family name suggests – it reads the generator, or is fixed by an exact identity over other columns, or identifies the cohort rather than the complex. stalled means it is defined but does not move on the corpus.

descriptor	flag	why
pitch	suspicious	reads the generator’s confidence rather than the interface: it is docking_angles’ incident_angle, and it out-discriminates every clean docking angle for that reason. Never use it as a feature.
fp_chi_r7	suspicious	determined: chi = b0 - b1 at the same radius.
fp_chi_r8	suspicious	determined: chi = b0 - b1 at the same radius.
D1_cell	suspicious	determined: D1 = 12 ** H_cell.
J_cell	suspicious	determined: J = H_cell * ln 12 / ln S_cell.
offset	suspicious	determined: offset = hypot(shift_u, shift_w).
n_loop_contacts	suspicious	determined: n_pep_contacts + n_mhc_contacts.
neg_energy	suspicious	determined: log_z + log_lik.
S_tot	suspicious	determined by K_tens and K_shear.
aniso	suspicious	determined by K_tens and K_shear.
couple_total	suspicious	determined: couple_pep + couple_mhc + couple_tcr.
crossing	suspicious	determined: abs(crossing_signed).
sc_gap_index	suspicious	determined: (sc_dh + sc_gap_mean) / 2.
dPhi_tcr_soft	suspicious	determined: dPhi_tra_soft + dPhi_trb_soft.
n_contacts_tm	suspicious	determined: the sum of the five ct_tm_* contact-type tallies.
n_contacts_tp	suspicious	determined: ct_tp_salt_bridge + ct_tp_aromatic + ct_tp_hydrophobic + ct_tp_other + n_hbond.
Phi_pep_mhc	suspicious	no receptor: constant across every structure of one epitope on one allele, so a receptor-ranking model reading it reaches the cohort label without reading an interface.
dPhi_pep_mhc	suspicious	no receptor; see Phi_pep_mhc.
Phi_pep_int	suspicious	no receptor; see Phi_pep_mhc.
n_pep_int	suspicious	no receptor; see Phi_pep_mhc.
mhc_class_bin	suspicious	no receptor: it is the MHC class, I or II. It is also constant on any single-class cohort – both receptor benchmarks are class I – so it contributes nothing there and separates the classes everywhere else.
m_erank_tp	suspicious	peptide-length coupled: -0.547 / -0.105, 58.3 per cent of variance beyond both lengths. It reads the class I bulge.
m_erank_tm	suspicious	CDR3-length coupled: -0.186 / -0.437, 69.4 per cent beyond both. It reads how much loop there is to spread over the helices.
m_gap_tp	suspicious	peptide-length coupled: -0.322 / +0.041, 90.8 per cent beyond both.
ca_cb_agreement_tm	suspicious	coupled to both lengths: -0.349 / -0.334, 70.5 per cent beyond them – the most length-loaded column here.
degree_evenness_tp	suspicious	peptide-length coupled: -0.450 / -0.006, 88.7 per cent beyond both. It reads the class I bulge.
frac_well_coordinated_tp	suspicious	peptide-length coupled: -0.440 / -0.064, 83.4 per cent beyond both; see degree_evenness_tp.
g_even_tcr	suspicious	peptide-length coupled: -0.368 / -0.061, 91.0 per cent beyond both.
g_loop_even	suspicious	CDR3-length coupled: -0.186 / -0.350, 87.7 per cent beyond both.
g_comp_frac	suspicious	CDR3-length coupled: -0.032 / +0.280, 92.7 per cent beyond both.
sc_gap_depth	suspicious	peptide-length coupled: +0.366 / +0.124, 71.8 per cent of variance beyond both lengths. A longer class I peptide bulges, and the receptor reaches further in where it does.
co_mhc	suspicious	CDR3-length coupled: +0.011 / +0.345, 88.0 per cent beyond both. Contact order divides by the target’s span, not the loop’s, so a longer loop spreads over more helix.
ct_tp_salt_bridge	stalled	only 3 distinct values over 1,707 modelled complexes: a salt bridge across the TCR:peptide interface is rare enough that the count is almost always 0. The TCR:MHC counterpart ct_tm_salt_bridge does move.