N-terminal protein-macrocycles enabled by conjugate addition/ring expansion cascade reactions.
Hughes, Owen R.; Tufail, Afzaal; Hutton, Esme; Nabarro, Joe; Howarth, Rachel; Yates, Nicholas D.; Whitwood, Adrian C.; Robson, Craig N.; Signoret, Nathalie; Fascione, Martin A.; Spicer, Christopher D.; Unsworth, William P.; Chemical science 17 (2026) 3320–3328; doi:10.1039/d5sc08044d

data_1576528
_publ_section_title
;
 N-terminal protein-macrocycles enabled by conjugate addition/ring
 expansion cascade reactions.
;
_journal_issue                   6
_journal_name_full               'Chemical science'
_journal_page_first              3320
_journal_page_last               3328
_journal_paper_doi               10.1039/d5sc08044d
_journal_volume                  17
_journal_year                    2026
_chemical_absolute_configuration unk
_chemical_formula_moiety         'C20 H25 N3 O4'
_chemical_formula_sum            'C20 H25 N3 O4'
_chemical_formula_weight         371.43
_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   difmap
_atom_sites_solution_primary     dual
_audit_creation_date             2023-03-06
_audit_creation_method
;
Olex2 1.5
(compiled 2023.02.24 svn.rf166f9f3 for OlexSys, GUI svn.r6725)
;
_audit_update_record
;
2024-10-15 deposited with the CCDC.	2025-12-12 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   9.14295(10)
_cell_length_b                   10.25505(13)
_cell_length_c                   20.8149(3)
_cell_measurement_reflns_used    7660
_cell_measurement_temperature    110.00(10)
_cell_measurement_theta_max      76.4760
_cell_measurement_theta_min      4.2280
_cell_volume                     1951.63(4)
_computing_cell_refinement       'CrysAlisPro 1.171.42.73a (Rigaku OD, 2022)'
_computing_data_collection       'CrysAlisPro 1.171.42.73a (Rigaku OD, 2022)'
_computing_data_reduction        'CrysAlisPro 1.171.42.73a (Rigaku OD, 2022)'
_computing_molecular_graphics    'Olex2 1.5 (Dolomanov et al., 2009)'
_computing_publication_material  'Olex2 1.5 (Dolomanov et al., 2009)'
_computing_structure_refinement  'SHELXL 2018/3 (Sheldrick, 2015)'
_computing_structure_solution    'SHELXT  (Sheldrick, 2015)'
_diffrn_ambient_environment      N~2~
_diffrn_ambient_temperature      110.00(10)
_diffrn_detector                 'Hybrid Pixel Array Detector'
_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   -106.00 -80.00   0.50    0.80    --  -48.95-138.00-140.00   52
  2  \w     40.00  98.00   0.50    0.80    --   48.95-131.00  35.00  116
  3  \w     44.00 124.00   0.50    3.20    --  107.75-143.00 -46.00  160
  4  \w     68.00 166.00   0.50    3.20    --  107.75   5.00  48.00  196
  5  \w   -100.00 -74.00   0.50    0.80    --  -48.95-125.00 150.00   52
  6  \w    -52.00 -15.00   0.50    0.80    --  -48.95  37.00  60.00   74
  7  \w   -116.00 -86.00   0.50    0.80    --  -48.95-125.00 -90.00   60
  8  \w    -61.00  27.00   0.50    0.80    --  -48.95  19.00-180.00  176
  9  \w     38.00  98.00   0.50    3.20    --  107.75 -99.00  30.00  120
 10  \w     42.00 107.00   0.50    3.20    --  107.75-125.00-150.00  130
 11  \w     89.00 116.00   0.50    3.20    --  107.75  77.00  90.00   54
 12  \w     37.00  77.00   0.50    3.20    --  107.75 -99.00 -30.00   80
 13  \w     99.00 124.00   0.50    3.20    --  107.75 125.00-180.00   50
 14  \w     37.00  80.00   0.50    3.20    --  107.75 -99.00 -60.00   86
;
_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      -0.0081269000
_diffrn_orient_matrix_UB_12      -0.1415615000
_diffrn_orient_matrix_UB_13      -0.0245599000
_diffrn_orient_matrix_UB_21      0.0063293000
_diffrn_orient_matrix_UB_22      0.0497132000
_diffrn_orient_matrix_UB_23      -0.0697670000
_diffrn_orient_matrix_UB_31      0.1681819000
_diffrn_orient_matrix_UB_32      -0.0088317000
_diffrn_orient_matrix_UB_33      0.0014157000
_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     0.0369
_diffrn_reflns_Laue_measured_fraction_full 1.000
_diffrn_reflns_Laue_measured_fraction_max 1.000
_diffrn_reflns_limit_h_max       10
_diffrn_reflns_limit_h_min       -8
_diffrn_reflns_limit_k_max       12
_diffrn_reflns_limit_k_min       -11
_diffrn_reflns_limit_l_max       24
_diffrn_reflns_limit_l_min       -24
_diffrn_reflns_number            9377
_diffrn_reflns_point_group_measured_fraction_full 1.000
_diffrn_reflns_point_group_measured_fraction_max 1.000
_diffrn_reflns_theta_full        67.064
_diffrn_reflns_theta_max         67.064
_diffrn_reflns_theta_min         4.248
_diffrn_source                   'micro-focus sealed X-ray tube'
_diffrn_source_type              'SuperNova (Cu) X-ray Source'
_exptl_absorpt_coefficient_mu    0.727
_exptl_absorpt_correction_T_max  1.000
_exptl_absorpt_correction_T_min  0.647
_exptl_absorpt_correction_type   gaussian
_exptl_absorpt_process_details
;
CrysAlisPro 1.171.42.73a (Rigaku Oxford Diffraction, 2022)
Numerical absorption correction based on gaussian integration over
a multifaceted crystal model
Empirical absorption correction using spherical harmonics,
implemented in SCALE3 ABSPACK scaling algorithm.
;
_exptl_crystal_colour            'clear colourless'
_exptl_crystal_colour_lustre     clear
_exptl_crystal_colour_primary    colourless
_exptl_crystal_density_diffrn    1.264
_exptl_crystal_description       block
_exptl_crystal_F_000             792
_exptl_crystal_recrystallization_method
'evaporation of an ethyl acetate solution'
_exptl_crystal_size_max          0.218
_exptl_crystal_size_mid          0.155
_exptl_crystal_size_min          0.043
_refine_diff_density_max         0.169
_refine_diff_density_min         -0.144
_refine_diff_density_rms         0.028
_refine_ls_abs_structure_details
;
 Flack x determined using 1393 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   0.11(9)
_refine_ls_extinction_coef       0.0010(2)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     'SHELXL-2018/3 (Sheldrick 2018)'
_refine_ls_goodness_of_fit_ref   1.029
_refine_ls_hydrogen_treatment    refall
_refine_ls_matrix_type           full
_refine_ls_number_parameters     345
_refine_ls_number_reflns         3479
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.029
_refine_ls_R_factor_all          0.0277
_refine_ls_R_factor_gt           0.0265
_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^)+(0.0273P)^2^+0.2077P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0640
_refine_ls_wR_factor_ref         0.0645
_reflns_Friedel_coverage         0.734
_reflns_Friedel_fraction_full    0.999
_reflns_Friedel_fraction_max     0.999
_reflns_number_gt                3360
_reflns_number_total             3479
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d5sc08044d2.cif
_cod_data_source_block           wpu23007
_cod_database_code               1576528
_shelx_shelxl_version_number     2018/3
_chemical_oxdiff_formula         'C20 H25 N3 O4'
_chemical_oxdiff_usercomment     'Owen Hughes OH25a'
_shelx_estimated_absorpt_t_max   0.969
_shelx_estimated_absorpt_t_min   0.858
_olex2_refinement_description
;
;
_shelx_res_checksum              35843
_shelx_hkl_checksum              6143
_olex2_date_sample_data_collection 2023-02-22
_olex2_date_sample_submission    2023-02-20
_olex2_exptl_crystal_mounting_method 'oil on 200 micrometre micromount'
_olex2_submission_original_sample_id OH25a
_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 1.154
_oxdiff_exptl_absorpt_empirical_full_min 0.872