ferritin_plms/esmc/utils/constants/physics.rs
1//! Physics constants for backbone geometry.
2
3/// Backbone heavy-atom positions in the canonical local frame.
4///
5/// Cα is at the origin, Cα→C is along +x, and N lies in the x–y plane.
6/// Rows: [N, CA, C]. Shape: `[3, 3]`. Units: Ångström.
7///
8/// Source: ideal peptide geometry (Engh & Huber, 1991).
9pub const BB_COORDINATES: [[f32; 3]; 3] = [
10 [-0.525, 1.363, 0.000], // N
11 [0.000, 0.000, 0.000], // CA (origin)
12 [1.526, 0.000, 0.000], // C
13];
14
15/// Ideal Cα–Cβ bond length (Å).
16pub const CA_CB_BOND_LENGTH: f32 = 1.522;
17
18/// Ideal Cα–C bond length (Å).
19pub const CA_C_BOND_LENGTH: f32 = 1.526;
20
21/// Ideal N–Cα bond length (Å).
22pub const N_CA_BOND_LENGTH: f32 = 1.458;
23
24/// Ideal peptide N–C bond length (Å).
25pub const PEPTIDE_N_C_BOND_LENGTH: f32 = 1.329;