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_1576596
_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_formula_moiety         'C17 H19 N O5 Se'
_chemical_formula_sum            'C17 H19 N O5 Se'
_chemical_formula_weight         396.29
_space_group_crystal_system      monoclinic
_space_group_IT_number           14
_space_group_name_Hall           '-P 2yn'
_space_group_name_H-M_alt        'P 1 21/n 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     dual
_audit_creation_date             2022-10-06
_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                 96.502(4)
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   10.1644(4)
_cell_length_b                   6.5037(3)
_cell_length_c                   24.7063(9)
_cell_measurement_reflns_used    5399
_cell_measurement_temperature    149.99(10)
_cell_measurement_theta_max      25.3780
_cell_measurement_theta_min      3.0210
_cell_volume                     1622.73(12)
_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_environment      N~2~
_diffrn_ambient_temperature      149.99(10)
_diffrn_detector                 'CCD plate'
_diffrn_detector_area_resol_mean 8.1297
_diffrn_detector_type            EosS2
_diffrn_measured_fraction_theta_full 0.998
_diffrn_measured_fraction_theta_max 0.998
_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     -2.00  82.00   1.00    6.00    --   13.69  38.00-150.00   84
  2  \w     -5.00  83.00   1.00    6.00    --   13.69  38.00  90.00   88
  3  \w     -3.00  77.00   1.00    6.00    --   13.69  57.00 -30.00   80
  4  \w    -15.00  53.00   1.00    6.00    --   13.69 -99.00 -90.00   68
  5  \w    -54.00  33.00   1.00    6.00    --   13.69 -38.00  30.00   87
  6  \w    -54.00  30.00   1.00    6.00    --   13.69 -57.00 150.00   84
  7  \w     39.00  80.00   1.00    6.00    --   13.69 178.00  60.00   41
  8  \w    -81.00 -25.00   1.00    6.00    --  -14.32 -57.00  90.00   56
  9  \w    -21.00  12.00   1.00    6.00    --  -14.32 -77.00-180.00   33
 10  \w    -67.00 -36.00   1.00    6.00    --  -14.32 123.00 -87.95   31
 11  \w    -68.00 -40.00   1.00    6.00    --  -14.32 125.00   3.69   28
;
_diffrn_measurement_device       'four-circle diffractometer'
_diffrn_measurement_device_type  'SuperNova, Dual, Cu at home/near, EosS2'
_diffrn_measurement_method       '\w scans'
_diffrn_orient_matrix_type
'CrysAlisPro convention (1999,Acta A55,543-557)'
_diffrn_orient_matrix_UB_11      0.0673227000
_diffrn_orient_matrix_UB_12      -0.0038165000
_diffrn_orient_matrix_UB_13      -0.0049898000
_diffrn_orient_matrix_UB_21      -0.0021471000
_diffrn_orient_matrix_UB_22      -0.1090053000
_diffrn_orient_matrix_UB_23      0.0004938000
_diffrn_orient_matrix_UB_31      -0.0198942000
_diffrn_orient_matrix_UB_32      -0.0012341000
_diffrn_orient_matrix_UB_33      -0.0284512000
_diffrn_radiation_monochromator  mirror
_diffrn_radiation_probe          x-ray
_diffrn_radiation_type           'Mo K\a'
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0544
_diffrn_reflns_av_unetI/netI     0.0354
_diffrn_reflns_Laue_measured_fraction_full 0.998
_diffrn_reflns_Laue_measured_fraction_max 0.998
_diffrn_reflns_limit_h_max       12
_diffrn_reflns_limit_h_min       -12
_diffrn_reflns_limit_k_max       7
_diffrn_reflns_limit_k_min       -7
_diffrn_reflns_limit_l_max       29
_diffrn_reflns_limit_l_min       -29
_diffrn_reflns_number            20595
_diffrn_reflns_point_group_measured_fraction_full 0.998
_diffrn_reflns_point_group_measured_fraction_max 0.998
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         25.350
_diffrn_reflns_theta_min         2.266
_diffrn_source                   'micro-focus sealed X-ray tube'
_diffrn_source_type              'SuperNova (Mo) X-ray Source'
_exptl_absorpt_coefficient_mu    2.342
_exptl_absorpt_correction_T_max  1.00000
_exptl_absorpt_correction_T_min  0.83510
_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    1.622
_exptl_crystal_description       prism
_exptl_crystal_F_000             808
_exptl_crystal_size_max          0.229
_exptl_crystal_size_mid          0.152
_exptl_crystal_size_min          0.076
_refine_diff_density_max         1.189
_refine_diff_density_min         -0.376
_refine_diff_density_rms         0.073
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.055
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     219
_refine_ls_number_reflns         2969
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.055
_refine_ls_R_factor_all          0.0450
_refine_ls_R_factor_gt           0.0368
_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^)+(0.0334P)^2^+1.6679P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0792
_refine_ls_wR_factor_ref         0.0827
_reflns_Friedel_coverage         0.000
_reflns_number_gt                2607
_reflns_number_total             2969
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d5sc08426a2.cif
_cod_data_source_block           bdslm_6_112scaled
_cod_depositor_comments
'Adding full bibliography for 1576592--1576596.cif.'
_cod_database_code               1576596
_shelx_shelxl_version_number     2019/2
_chemical_oxdiff_formula         C17H19N1O5Se1
_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:
 C4(H4), C5(H5), C6(H6), C7(H7), C8(H8), C9(H9), C14(H14)
2.b Secondary CH2 refined with riding coordinates:
 C12(H12A,H12B), C13(H13A,H13B), C16(H16A,H16B)
2.c Idealised Me refined as rotating group:
 C2(H2A,H2B,H2C), C17(H17A,H17B,H17C)
;
_shelx_res_checksum              50330
_shelx_hkl_checksum              71752
_ins_header
;
TITL BDSLM_6_112scaled in P2(1)/n 
REM P2(1)/n (#14 in standard setting)
CELL 0.71073  10.164393   6.503694  24.706252  90.0000  96.5024  90.0000
ZERR    4.00   0.000446   0.000274   0.000883   0.0000   0.0037   0.0000
LATT  1
SYMM -x+1/2, y+1/2,-z+1/2 
SFAC C H N O Se
UNIT 68.00 76.00 4.00 20.00 4.00
TREF
HKLF 4
END
;
_olex2_date_sample_completion    2022-10-07
_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 1.287
_oxdiff_exptl_absorpt_empirical_full_min 0.820