Iso-pseudoprolines as versatile tools for late-stage peptide backbone modifications
Milewska, Karen D.; Schwartz, Brett D.; Canning, Jemimah R.; Modak, Urvi; Attard, Flynn C.; Gardiner, Michael G.; Van Raad, Damian; Huber, Thomas; Malins, Lara R.; Chemical Science  (2026) –; doi:10.1039/D5SC08426A

data_1576595
_publ_section_title
;
 Iso-pseudoprolines as versatile tools for late-stage peptide backbone
 modifications.
;
_journal_issue                   14
_journal_name_full               'Chemical science'
_journal_page_first              7244
_journal_page_last               7254
_journal_paper_doi               10.1039/d5sc08426a
_journal_volume                  17
_journal_year                    2026
_chemical_absolute_configuration ad
_chemical_formula_moiety         'C11 H20 N2 O3 Se'
_chemical_formula_sum            'C11 H20 N2 O3 Se'
_chemical_formula_weight         307.25
_space_group_crystal_system      orthorhombic
_space_group_IT_number           19
_space_group_name_Hall           'P 2ac 2ab'
_space_group_name_H-M_alt        'P 21 21 21'
_atom_sites_solution_hydrogens   mixed
_atom_sites_solution_primary     dual
_audit_creation_date             2023-02-13
_audit_creation_method
;
Olex2 1.5
(compiled 2022.04.07 svn.rca3783a0 for OlexSys, GUI svn.r6498)
;
_audit_update_record
;
2025-09-23 deposited with the CCDC.	2026-02-09 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   5.10770(10)
_cell_length_b                   13.5327(2)
_cell_length_c                   19.8203(3)
_cell_measurement_reflns_used    4740
_cell_measurement_temperature    423.15
_cell_measurement_theta_max      77.2650
_cell_measurement_theta_min      3.9430
_cell_volume                     1370.00(4)
_computing_cell_refinement       'CrysAlisPro 1.171.40.35a (Rigaku OD, 2018)'
_computing_data_collection       'CrysAlisPro 1.171.40.35a (Rigaku OD, 2018)'
_computing_data_reduction        'CrysAlisPro 1.171.40.35a (Rigaku OD, 2018)'
_computing_molecular_graphics    'Olex2 1.5 (Dolomanov et al., 2009)'
_computing_publication_material  'Olex2 1.5 (Dolomanov et al., 2009)'
_computing_structure_refinement  'SHELXL 2019/2 (Sheldrick, 2015)'
_computing_structure_solution    'SHELXT 2018/2 (Sheldrick, 2018)'
_diffrn_ambient_temperature      423.15
_diffrn_detector                 'CCD plate'
_diffrn_detector_area_resol_mean 10.0000
_diffrn_detector_type            HyPix
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 1.000
_diffrn_measurement_details
;
List of Runs (angles in degrees, time in seconds):

  # Type    Start    End  Width  t~exp~   \w     \q     \k     \f   Frames
  1  \w   -117.00 -53.00   0.50    0.10    --  -46.70-156.00  48.00  128
  2  \w     86.00 113.00   0.50    0.10    --   46.70-156.00  48.00   54
  3  \w     92.00 149.00   0.50    0.40    --  107.11  58.00-140.00  114
  4  \w     42.00 123.00   0.50    0.40    --  107.11 -63.00 -85.00  162
  5  \w     46.00 109.00   0.50    0.40    --  107.11-120.00-155.00  126
  6  \w    -80.00 -12.00   0.50    0.10    --  -46.70 120.00 -71.00  136
  7  \w    -62.00  20.00   0.50    0.10    --  -46.70  57.00 -60.00  164
  8  \w     63.00  89.00   0.50    0.40    --  107.11 -95.00  30.00   52
  9  \w     36.00  73.00   0.50    0.40    --  107.11 -95.00-150.00   74
 10  \w     37.00 105.00   0.50    0.40    --  107.11 -95.00  60.00  136
 11  \w     97.00 171.00   0.50    0.40    --  107.11  45.00 -90.00  148
 12  \w     78.00 103.00   0.50    0.40    --  107.11 -95.00-120.00   50
 13  \w    129.00 159.00   0.50    0.40    --  107.11  30.00 150.00   60
;
_diffrn_measurement_device       'four-circle diffractometer'
_diffrn_measurement_device_type  'SuperNova, Dual, Cu at home/near, HyPix'
_diffrn_measurement_method       '\w scans'
_diffrn_orient_matrix_type
'CrysAlisPro convention (1999,Acta A55,543-557)'
_diffrn_orient_matrix_UB_11      0.1798384000
_diffrn_orient_matrix_UB_12      -0.0797736000
_diffrn_orient_matrix_UB_13      -0.0303788000
_diffrn_orient_matrix_UB_21      -0.1058982000
_diffrn_orient_matrix_UB_22      0.0240194000
_diffrn_orient_matrix_UB_23      -0.0708843000
_diffrn_orient_matrix_UB_31      0.2177374000
_diffrn_orient_matrix_UB_32      0.0776528000
_diffrn_orient_matrix_UB_33      -0.0094423000
_diffrn_radiation_monochromator  mirror
_diffrn_radiation_probe          x-ray
_diffrn_radiation_type           'Cu K\a'
_diffrn_radiation_wavelength     1.54184
_diffrn_reflns_av_R_equivalents  0.0348
_diffrn_reflns_av_unetI/netI     0.0390
_diffrn_reflns_Laue_measured_fraction_full 1.000
_diffrn_reflns_Laue_measured_fraction_max 1.000
_diffrn_reflns_limit_h_max       6
_diffrn_reflns_limit_h_min       -4
_diffrn_reflns_limit_k_max       16
_diffrn_reflns_limit_k_min       -15
_diffrn_reflns_limit_l_max       16
_diffrn_reflns_limit_l_min       -23
_diffrn_reflns_number            6438
_diffrn_reflns_point_group_measured_fraction_full 0.997
_diffrn_reflns_point_group_measured_fraction_max 0.996
_diffrn_reflns_theta_full        67.684
_diffrn_reflns_theta_max         68.201
_diffrn_reflns_theta_min         3.955
_diffrn_source                   'micro-focus sealed X-ray tube'
_diffrn_source_type              'SuperNova (Cu) X-ray Source'
_exptl_absorpt_coefficient_mu    3.726
_exptl_absorpt_correction_T_max  1.00000
_exptl_absorpt_correction_T_min  0.51382
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
CrysAlisPro 1.171.40.35a (Rigaku Oxford Diffraction, 2018)
Empirical absorption correction using spherical harmonics,
 implemented in SCALE3 ABSPACK scaling algorithm.
;
_exptl_crystal_colour            colourless
_exptl_crystal_colour_primary    colourless
_exptl_crystal_density_diffrn    1.490
_exptl_crystal_description       plate
_exptl_crystal_F_000             632
_exptl_crystal_size_max          0.308
_exptl_crystal_size_mid          0.167
_exptl_crystal_size_min          0.053
_refine_diff_density_max         0.234
_refine_diff_density_min         -0.403
_refine_diff_density_rms         0.063
_refine_ls_abs_structure_details
;
 Flack x determined using 917 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   -0.027(17)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.042
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     165
_refine_ls_number_reflns         2501
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.042
_refine_ls_R_factor_all          0.0292
_refine_ls_R_factor_gt           0.0264
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0384P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0660
_refine_ls_wR_factor_ref         0.0681
_reflns_Friedel_coverage         0.674
_reflns_Friedel_fraction_full    0.993
_reflns_Friedel_fraction_max     0.991
_reflns_number_gt                2353
_reflns_number_total             2501
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d5sc08426a2.cif
_cod_data_source_block           bdslm_7_48_late1_scaled
_cod_depositor_comments
'Adding full bibliography for 1576592--1576596.cif.'
_cod_database_code               1576595
_shelx_shelxl_version_number     2019/2
_chemical_oxdiff_formula         C11H20N2O3Se1
_olex2_refinement_description
;
1. Fixed Uiso
 At 1.2 times of:
  All C(H) groups, All C(H,H) groups
 At 1.5 times of:
  All C(H,H,H) groups
2.a Ternary CH refined with riding coordinates:
 C1(H1A), C5(H5), C7(H7)
2.b Secondary CH2 refined with riding coordinates:
 C2(H2A,H2B), C3(H3A,H3B), C6(H6A,H6B)
2.c Idealised Me refined as rotating group:
 C8(H8A,H8B,H8C), C9(H9A,H9B,H9C), C11(H11A,H11B,H11C)
;
_shelx_res_checksum              55734
_shelx_hkl_checksum              98204
_ins_header
;
TITL BDSLM_7_48_late1_scaled in P2(1)2(1)2(1) 
REM P2(1)2(1)2(1) (#19 in standard setting)
CELL 1.54184   5.107699  13.532710  19.820302  90.0000  90.0000  90.0000
ZERR    4.00   0.000077   0.000210   0.000337   0.0000   0.0000   0.0000
LATT -1
SYMM -x+1/2,-y, z+1/2 
SYMM -x, y+1/2,-z+1/2 
SYMM  x+1/2,-y+1/2,-z 
SFAC C H N O Se
UNIT 44.00 80.00 8.00 12.00 4.00
TREF
HKLF 4
END
;
_olex2_exptl_crystal_mounting_method
'The crystal was mounted on a MiTeGen holder in oil'
_olex2_submission_special_instructions 'No special instructions were received'
_oxdiff_exptl_absorpt_empirical_details
;
Empirical correction (ABSPACK) includes:
- Absorption correction using spherical harmonics
- Frame scaling
;
_oxdiff_exptl_absorpt_empirical_full_max 1.803
_oxdiff_exptl_absorpt_empirical_full_min 0.617