[phenixbb] Refining peptides with beta-amino acids

Bram Mylemans bram.mylemans at bristol.ac.uk
Mon Jun 26 14:57:12 PDT 2023


Dear experts,

I’m trying to refine a crystal structure of a peptide that contains some beta-amino acids. I have tried generating restraints with elbow from a sdf file. I changed the naming of the atoms to conform with the protein naming and added the L-peptide linking tag. This seems to work for refining and also local refine in coot works.

However, the peptide bond is not kept planar. Does anyone have an idea how to make sure the amide bond is correctly constrained?

I have included the restrained file I made for L-beta-Leucine below for reference.

Best wishes,
----------
Dr. Bram Mylemans

Post-doctoral Research Associate
Woolfson group

School of Chemistry
University of Bristol


# electronic Ligand Builder and Optimisation Workbench (eLBOW)
#   - a module of PHENIX version 1.20.1-4487-
#   - file written: Sun May 14 14:31:25 2023
#
#   Inital geometry file: a 60 line input string
#   Ligand name: (3S)-3-amino-5-methylhexanoic acid
#   Quantum optimisation: True
#   Method: uhf
#   Random seed: 3628800
#   SMILES string: CC(C)C[C at H](N)CC(O)=O
#
data_comp_list
loop_
_chem_comp.id
_chem_comp.three_letter_code
_chem_comp.name
_chem_comp.group
_chem_comp.number_atoms_all
_chem_comp.number_atoms_nh
_chem_comp.desc_level
B3L        B3L '(3S)-3-amino-5-methylhexanoic acid' L-peptide 24 10 .
#
data_comp_B3L
#
loop_
_chem_comp_atom.comp_id
_chem_comp_atom.atom_id
_chem_comp_atom.type_symbol
_chem_comp_atom.type_energy
_chem_comp_atom.charge
_chem_comp_atom.partial_charge
_chem_comp_atom.x
_chem_comp_atom.y
_chem_comp_atom.z
B3L         O      O   O      0  -0.621   -0.0468   -0.0672    0.0379
B3L         C      C   C      0   0.403    1.2030   -0.0409   -0.0524
B3L         CA     C   CH2    0  -0.215    2.0004    0.0099    1.2717
B3L         CB     C   CH1    0   0.109    1.5936   -1.1463    2.1941
B3L         N      N   NH2    0  -0.452    2.4198   -2.3233    1.9111
B3L         CG     C   CH2    0  -0.173    1.7636   -0.6462    3.6485
B3L         CD     C   CH1    0  -0.040    1.5804   -1.7407    4.6994
B3L         CE2    C   CH3    0  -0.160    1.9937   -1.1916    6.0651
B3L         CE1    C   CH3    0  -0.159    0.1402   -2.2497    4.7124
B3L         HA     H   HCH2   0   0.055    3.0941    0.0115    1.0876
B3L         HAA    H   HCH2   0   0.036    1.7870    0.9871    1.7352
B3L         HB     H   HCH1   0   0.088    0.5145   -1.4120    2.0199
B3L         HN     H   HNH2   0   0.153    1.9179   -3.1939    1.9355
B3L         HG     H   HCH2   0   0.049    2.7650   -0.1815    3.7540
B3L         HGA    H   HCH2   0   0.063    1.0542    0.1844    3.8432
B3L         HD     H   HCH1   0   0.048    2.2575   -2.6020    4.4708
B3L        H3E2    H   HCH3   0   0.033    2.4606   -1.9617    6.6915
B3L        H2E2    H   HCH3   0   0.049    2.7302   -0.3796    5.9910
B3L        H1E2    H   HCH3   0   0.045    1.1543   -0.7788    6.6358
B3L        H3E1    H   HCH3   0   0.045    0.0304   -3.1957    4.1675
B3L        H2E1    H   HCH3   0   0.034   -0.2410   -2.4354    5.7240
B3L        H1E1    H   HCH3   0   0.068   -0.5687   -1.5528    4.2450
B3L         OXT    O   OC    -1  -0.606    1.8564   -0.0003   -1.1279
B3L         HNA    H   HNH2   0   0.147    3.2587   -2.3840    2.4671
#
loop_
_chem_comp_bond.comp_id
_chem_comp_bond.atom_id_1
_chem_comp_bond.atom_id_2
_chem_comp_bond.type
_chem_comp_bond.value_dist
_chem_comp_bond.value_dist_esd
B3L   C       O     single        1.253 0.015
B3L   C       OXT   single        1.259 0.016
B3L   CA      C     single        1.546 0.037
B3L   CB      CA    single        1.534 0.036
B3L   CB      HB    single        1.125 0.040
B3L   N       CB    single        1.466 0.036
B3L   N       HNA   single        1.008 0.037
B3L   CG      CB    single        1.547 0.037
B3L   CG      HG    single        1.109 0.039
B3L   CD      CG    single        1.528 0.035
B3L   CD      CE1   single        1.528 0.035
B3L   CE2     CD    single        1.529 0.035
B3L   CE2    H1E2   single        1.096 0.038
B3L   CE1    H1E1   single        1.098 0.038
B3L   CE1    H3E1   single        1.097 0.038
B3L   HA      CA    single        1.109 0.037
B3L   HAA     CA    single        1.102 0.040
B3L   HN      N     single        1.005 0.037
B3L   HGA     CG    single        1.110 0.039
B3L   HD      CD    single        1.119 0.040
B3L  H3E2     CE2   single        1.097 0.038
B3L  H2E2     CE2   single        1.099 0.038
B3L  H2E1     CE1   single        1.097 0.038
#
loop_
_chem_comp_angle.comp_id
_chem_comp_angle.atom_id_1
_chem_comp_angle.atom_id_2
_chem_comp_angle.atom_id_3
_chem_comp_angle.value_angle
_chem_comp_angle.value_angle_esd
B3L   OXT     C       CA          117.56 2.401
B3L   CA      C       O           116.95 2.270
B3L   OXT     C       O           125.42 1.837
B3L   HAA     CA      HA          105.03 2.935
B3L   HAA     CA      CB          111.34 2.722
B3L   HA      CA      CB          111.25 2.583
B3L   HAA     CA      C           106.82 2.670
B3L   HA      CA      C           111.50 2.415
B3L   CB      CA      C           110.69 2.417
B3L   HB      CB      CG          109.11 2.657
B3L   CG      CB      N           112.27 2.657
B3L   HB      CB      N           108.74 2.657
B3L   CG      CB      CA          107.01 2.247
B3L   N       CB      CA          109.86 2.386
B3L   HB      CB      CA          109.83 2.388
B3L   HNA     N       HN          110.49 3.000
B3L   HN      N       CB          114.17 2.677
B3L   HNA     N       CB          114.27 2.682
B3L   HGA     CG      HG          104.29 2.953
B3L   HGA     CG      CD          109.80 2.649
B3L   HG      CG      CD          110.06 1.813
B3L   HGA     CG      CB          109.67 2.659
B3L   CD      CG      CB          113.69 2.657
B3L   HG      CG      CB          108.91 2.671
B3L   HD      CD      CE1         108.40 2.672
B3L   HD      CD      CE2         107.17 2.674
B3L   CE1     CD      CE2         111.53 2.389
B3L   HD      CD      CG          109.76 2.723
B3L   CE2     CD      CG          108.95 2.259
B3L   CE1     CD      CG          110.95 2.656
B3L  H1E2     CE2    H2E2         105.67 2.934
B3L  H2E2     CE2    H3E2         105.78 2.934
B3L  H1E2     CE2    H3E2         107.05 2.933
B3L  H2E2     CE2     CD          112.73 2.662
B3L  H3E2     CE2     CD          111.91 2.665
B3L  H1E2     CE2     CD          113.17 2.686
B3L  H1E1     CE1    H2E1         106.00 2.935
B3L  H2E1     CE1    H3E1         106.10 2.936
B3L  H1E1     CE1    H3E1         105.73 2.935
B3L  H2E1     CE1     CD          113.07 2.437
B3L  H3E1     CE1     CD          112.17 2.708
B3L  H1E1     CE1     CD          113.17 2.649
#
loop_
_chem_comp_tor.comp_id
_chem_comp_tor.id
_chem_comp_tor.atom_id_1
_chem_comp_tor.atom_id_2
_chem_comp_tor.atom_id_3
_chem_comp_tor.atom_id_4
_chem_comp_tor.value_angle
_chem_comp_tor.value_angle_esd
_chem_comp_tor.period
B3L Var_01         CB      CA      C       O            54.55  30.0 2
B3L Var_02         CE1     CD      CG      CB          -66.07  30.0 1
B3L Var_03        H1E1     CE1     CD      CG          -19.34  30.0 3
B3L Var_04        H1E2     CE2     CD      CG           93.46  30.0 3
#
loop_
_chem_comp_chir.comp_id
_chem_comp_chir.id
_chem_comp_chir.atom_id_centre
_chem_comp_chir.atom_id_1
_chem_comp_chir.atom_id_2
_chem_comp_chir.atom_id_3
_chem_comp_chir.volume_sign
B3L chir_01   CB      CA      N       CG    negativ
#
loop_
_chem_comp_plane_atom.comp_id
_chem_comp_plane_atom.plane_id
_chem_comp_plane_atom.atom_id
_chem_comp_plane_atom.dist_esd
B3L plan-1      O 0.020
B3L plan-1      C 0.020
B3L plan-1     CA 0.020
B3L plan-1    OXT 0.020

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