How mithramycin stereochemistry dictates its structure and DNA binding function.
Hou, Caixia; Rohr, Jürgen; Parkin, Sean; Tsodikov, Oleg V.; MedChemComm 10 (2019) 735–741; doi:10.1039/c9md00100j

data_7123230
_publ_section_title
;
 How mithramycin stereochemistry dictates its structure and DNA binding
 function.
;
_journal_issue                   5
_journal_name_full               MedChemComm
_journal_page_first              735
_journal_page_last               741
_journal_paper_doi               10.1039/c9md00100j
_journal_volume                  10
_journal_year                    2019
_chemical_absolute_configuration rm
_chemical_formula_sum            'C250.29 H340.86 Mg2 N4 O141.24'
_chemical_formula_weight         5714.18
_chemical_name_systematic        mtm-saphe-Mg2+
_space_group_crystal_system      monoclinic
_space_group_IT_number           4
_space_group_name_Hall           'P 2yb'
_space_group_name_H-M_alt        'P 1 21 1'
_symmetry_space_group_name_Hall  'P 2yb'
_symmetry_space_group_name_H-M   'P 1 21 1'
_atom_sites_solution_hydrogens   difmap
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-2018/3
_audit_update_record
;
2019-02-12 deposited with the CCDC.    2019-03-28 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 104.17(3)
_cell_angle_gamma                90
_cell_formula_units_Z            2
_cell_length_a                   28.073(5)
_cell_length_b                   21.531(4)
_cell_length_c                   28.536(5)
_cell_measurement_reflns_used    51177
_cell_measurement_temperature    100(2)
_cell_measurement_theta_max      24.09
_cell_measurement_theta_min      1.30
_cell_volume                     16723(6)
_computing_cell_refinement       '<i>APEX2</i> (Bruker-AXS, 2006)'
_computing_data_collection       '<i>APEX2</i> (Bruker-AXS, 2006)'
_computing_data_reduction        '<i>APEX2</i> (Bruker-AXS, 2006)'
_computing_molecular_graphics    '<i>XP in SHELXTL</i> (Sheldrick, 2008)'
_computing_publication_material
'<i>SHELX</i> (Sheldrick, 2008) and <i>CIFFIX</i> (Parkin, 2013)'
_computing_structure_refinement  '<i>SHELXL-2018/3</i> (Sheldrick, 2015b)'
_computing_structure_solution    '<i>SHELXT</i> (Sheldrick, 2015a)'
_diffrn_ambient_temperature      100(2)
_diffrn_measured_fraction_theta_full 0.981
_diffrn_measured_fraction_theta_max 0.981
_diffrn_measurement_device_type  'kappa-axis goniometer'
_diffrn_measurement_method       '\f and \w shutterless scans'
_diffrn_radiation_monochromator  'silicon 111'
_diffrn_radiation_type           synchrotron
_diffrn_radiation_wavelength     0.97872
_diffrn_reflns_av_R_equivalents  0.060
_diffrn_reflns_av_unetI/netI     0.0550
_diffrn_reflns_Laue_measured_fraction_full 0.981
_diffrn_reflns_Laue_measured_fraction_max 0.981
_diffrn_reflns_number            19692
_diffrn_reflns_point_group_measured_fraction_full 0.969
_diffrn_reflns_point_group_measured_fraction_max 0.969
_diffrn_reflns_theta_full        24.091
_diffrn_reflns_theta_max         24.091
_diffrn_reflns_theta_min         1.302
_diffrn_source                   'APS, beamline 22ID'
_exptl_absorpt_coefficient_mu    0.216
_exptl_absorpt_correction_T_max  0.989
_exptl_absorpt_correction_T_min  0.979
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   '<i>Scalepack</i> (Otwinowski & Minor, 2006)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.135
_exptl_crystal_description       block
_exptl_crystal_F_000             6049
_exptl_crystal_recrystallization_method 'hanging drop'
_exptl_crystal_size_max          0.100
_exptl_crystal_size_mid          0.100
_exptl_crystal_size_min          0.050
_refine_diff_density_max         0.556
_refine_diff_density_min         -0.341
_refine_diff_density_rms         0.056
_refine_ls_abs_structure_details
; 
Flack 'x' determined using 5659 quotients [(I+)-(I-)]/[(I+)+(I-)] 
[Parsons, Flack and Wagner (2013)]. 
;
_refine_ls_abs_structure_Flack   -3.03(9)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.108
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     3733
_refine_ls_number_reflns         19685
_refine_ls_number_restraints     6969
_refine_ls_restrained_S_all      1.048
_refine_ls_R_factor_all          0.1026
_refine_ls_R_factor_gt           0.0795
_refine_ls_shift/su_max          0.012
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.1677P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.2076
_refine_ls_wR_factor_ref         0.2318
_reflns_Friedel_coverage         0.896
_reflns_Friedel_fraction_full    0.956
_reflns_Friedel_fraction_max     0.956
_reflns_number_gt                14682
_reflns_number_total             19685
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            c9md00100j1.cif
_cod_data_source_block           mtmsaphe
_cod_depositor_comments
'Adding full bibliography for 7123230--7123231.cif.'
_cod_database_code               7123230
_shelx_shelxl_version_number     2018/3
_shelx_estimated_absorpt_t_min   0.979
_shelx_estimated_absorpt_t_max   0.989
_exptl_absorpt_special_details
; 
In addition to absorption, multi-scan techniques also correct other slowly 
varying changes in scale factor over reciprocal space, such as those caused 
by X-ray beam inhomogeneity, goniometer imperfection, crystal decomposition, 
crystal longer than the X-ray beam cross section, absorption by the crystal 
mount etc.  These account, by and large, for much of the difference between 
estimated values of Tmin and Tmax and the _exptl_absorpt_correction_ values. 
;
_shelx_res_checksum              36213
_shelx_fab_checksum              59739