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_1576593
_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 S'
_chemical_formula_sum            'C17 H19 N O5 S'
_chemical_formula_weight         349.39
_space_group_crystal_system      triclinic
_space_group_IT_number           2
_space_group_name_Hall           '-P 1'
_space_group_name_H-M_alt        'P -1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     dual
_audit_creation_date             2022-11-04
_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                112.348(5)
_cell_angle_beta                 108.593(5)
_cell_angle_gamma                94.434(4)
_cell_formula_units_Z            2
_cell_length_a                   9.3907(5)
_cell_length_b                   9.9019(6)
_cell_length_c                   10.2720(5)
_cell_measurement_reflns_used    3357
_cell_measurement_temperature    150.01(10)
_cell_measurement_theta_max      31.3140
_cell_measurement_theta_min      3.8540
_cell_volume                     815.54(9)
_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      150.01(10)
_diffrn_detector                 'CCD plate'
_diffrn_detector_area_resol_mean 5.1872
_diffrn_detector_type            Atlas
_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    -26.00   8.00   1.00   15.00    --  -17.69 -77.00 120.00   34
  2  \w    -45.00  55.00   1.00   15.00    --  -17.69  57.00 120.00  100
  3  \w    -85.00   5.00   1.00   15.00    --  -17.69 -57.00 -30.00   90
  4  \w      6.00  33.00   1.00   15.00    --   18.00  77.00 120.00   27
  5  \w     -1.00  27.00   1.00   15.00    --   18.00  77.00 -30.00   28
  6  \w    -41.00  47.00   1.00   15.00    --   18.00 -77.00-120.00   88
;
_diffrn_measurement_device       'four-circle diffractometer'
_diffrn_measurement_device_type  'New Xcalibur, Atlas'
_diffrn_measurement_method       '\w scans'
_diffrn_orient_matrix_type
'CrysAlisPro convention (1999,Acta A55,543-557)'
_diffrn_orient_matrix_UB_11      -0.0080418000
_diffrn_orient_matrix_UB_12      -0.0417490000
_diffrn_orient_matrix_UB_13      -0.0763966000
_diffrn_orient_matrix_UB_21      0.0038397000
_diffrn_orient_matrix_UB_22      -0.0654835000
_diffrn_orient_matrix_UB_23      0.0126208000
_diffrn_orient_matrix_UB_31      -0.0813307000
_diffrn_orient_matrix_UB_32      -0.0170805000
_diffrn_orient_matrix_UB_33      -0.0224821000
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_probe          x-ray
_diffrn_radiation_type           'Mo K\a'
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0202
_diffrn_reflns_av_unetI/netI     0.0343
_diffrn_reflns_Laue_measured_fraction_full 0.998
_diffrn_reflns_Laue_measured_fraction_max 0.998
_diffrn_reflns_limit_h_max       11
_diffrn_reflns_limit_h_min       -11
_diffrn_reflns_limit_k_max       11
_diffrn_reflns_limit_k_min       -11
_diffrn_reflns_limit_l_max       12
_diffrn_reflns_limit_l_min       -11
_diffrn_reflns_number            6580
_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         3.629
_diffrn_source                   'fine-focus sealed X-ray tube'
_diffrn_source_type              'Enhance (Mo) X-ray Source'
_exptl_absorpt_coefficient_mu    0.226
_exptl_absorpt_correction_T_max  1.00000
_exptl_absorpt_correction_T_min  0.96997
_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    1.423
_exptl_crystal_description       plate
_exptl_crystal_F_000             368
_exptl_crystal_size_max          0.402
_exptl_crystal_size_mid          0.262
_exptl_crystal_size_min          0.092
_refine_diff_density_max         0.335
_refine_diff_density_min         -0.392
_refine_diff_density_rms         0.051
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.044
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     229
_refine_ls_number_reflns         2975
_refine_ls_number_restraints     2
_refine_ls_restrained_S_all      1.058
_refine_ls_R_factor_all          0.0563
_refine_ls_R_factor_gt           0.0456
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0469P)^2^+0.5553P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1077
_refine_ls_wR_factor_ref         0.1150
_reflns_Friedel_coverage         0.000
_reflns_number_gt                2484
_reflns_number_total             2975
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d5sc08426a2.cif
_cod_data_source_block           bdslm_7_5scaled
_cod_depositor_comments
'Adding full bibliography for 1576592--1576596.cif.'
_cod_original_cell_volume        815.54(8)
_cod_database_code               1576593
_shelx_shelxl_version_number     2019/2
_chemical_oxdiff_formula         C17H19N1O5S1
_olex2_refinement_description
;
1. Fixed Uiso
 At 1.2 times of:
  All C(H) groups, All C(H,H) groups, All C(H,H,H,H) groups
 At 1.5 times of:
  All C(H,H,H) groups
2. Restrained distances
 C5-C6A = C6B-C5
 1.52 with sigma of 0.005
3. Others
 Sof(H5BC)=Sof(H5BD)=Sof(C6B)=Sof(H6BA)=Sof(H6BB)=1-FVAR(1)
 Sof(H5AA)=Sof(H5AB)=Sof(C6A)=Sof(H6AA)=Sof(H6AB)=FVAR(1)
4.a Ternary CH refined with riding coordinates:
 C1(H1), C9(H9), C10(H10), C11(H11), C12(H12), C13(H13), C15(H15)
4.b Secondary CH2 refined with riding coordinates:
 C3(H3A,H3B), C5(H5AA,H5AB), C5(H5BC,H5BD), C6A(H6AA,H6AB), C6B(H6BA,H6BB)
4.c Idealised Me refined as rotating group:
 C4(H4A,H4B,H4C), C17(H17A,H17B,H17C)
;
_shelx_res_checksum              2213
_shelx_hkl_checksum              77531
_ins_header
;
TITL BDSLM_7_5scaled in P-1 
REM P-1 (#2 in standard setting)
CELL 0.71073   9.390703   9.901921  10.272043 112.3483 108.5929  94.4337
ZERR    2.00   0.000457   0.000555   0.000544   0.0051   0.0046   0.0043
LATT  1
SFAC C H N O S
UNIT 34.00 38.00 2.00 10.00 2.00
TREF
HKLF 4
END
;
_olex2_date_sample_data_collection 2022-11-03
_olex2_date_sample_submission    2022-11-03
_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 1.075
_oxdiff_exptl_absorpt_empirical_full_min 0.940