Sequence-Specific Unusual (1→2)-Type Helical Turns in α/β-Hybrid Peptides
Panchami Prabhakaran; Sangram S. Kale; Vedavati G. Puranik; P. R. Rajamohanan; Olga Chetina; Judith A. K. Howard; Hans-Jörg Hofmann; Gangadhar J. Sanjayan; Journal of the American Chemical Society 130 (2008) 17743–17754; doi:10.1021/ja804297f

data_4108915
_publ_contact_author_address
;
Chemistry Department,
University of Durham,
South Rd.,
Durham
DH1 3LE
UK
;
_publ_contact_author_email       olga.chetina@durham.ac.uk
_publ_contact_author_fax         '0191 384 4737'
_publ_contact_author_name        'Dr. Olga Chetina'
_publ_contact_author_phone       '0191 334 2004'
_publ_section_title
;
 Sequence-Specific Unusual (1\\rightarrow2)-Type Helical Turns in
 \a/\b-Hybrid Peptides
;
_journal_name_full               'Journal of the American Chemical Society'
_journal_page_first              17743
_journal_page_last               17754
_journal_paper_doi               10.1021/ja804297f
_journal_volume                  130
_journal_year                    2008
_chemical_formula_moiety         'C20 H28 N4 O5'
_chemical_formula_sum            'C20 H28 N4 O5'
_chemical_formula_weight         404.46
_chemical_name_common            peptide
_space_group_IT_number           61
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  '-P 2ac 2ab'
_symmetry_space_group_name_H-M   'P b c a'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            8
_cell_length_a                   10.8666(10)
_cell_length_b                   16.478(3)
_cell_length_c                   24.053(2)
_cell_measurement_reflns_used    1493
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      17.342
_cell_measurement_theta_min      2.399
_cell_volume                     4306.9(9)
_computing_cell_refinement       'BRUKER SAINT'
_computing_data_collection       'BRUKER SMART'
_computing_data_reduction        'BRUKER SAINT'
_computing_molecular_graphics    'SHELXTL and PLATON'
_computing_publication_material  SHELXTL
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 1.000
_diffrn_measurement_device       'Bruker Smart APEX'
_diffrn_measurement_device_type  'CCD Area Detector'
_diffrn_measurement_method       'Omega Scan'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0839
_diffrn_reflns_av_sigmaI/netI    0.0597
_diffrn_reflns_limit_h_max       10
_diffrn_reflns_limit_h_min       -12
_diffrn_reflns_limit_k_max       19
_diffrn_reflns_limit_k_min       -17
_diffrn_reflns_limit_l_max       28
_diffrn_reflns_limit_l_min       -26
_diffrn_reflns_number            20702
_diffrn_reflns_theta_full        25.00
_diffrn_reflns_theta_max         25.00
_diffrn_reflns_theta_min         2.40
_exptl_absorpt_coefficient_mu    0.091
_exptl_absorpt_correction_T_max  0.9915
_exptl_absorpt_correction_T_min  0.9807
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'Bruker SADABS'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.248
_exptl_crystal_description       plate
_exptl_crystal_F_000             1728
_exptl_crystal_size_max          0.22
_exptl_crystal_size_mid          0.18
_exptl_crystal_size_min          0.09
_refine_diff_density_max         0.211
_refine_diff_density_min         -0.155
_refine_diff_density_rms         0.038
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.108
_refine_ls_hydrogen_treatment    riding
_refine_ls_matrix_type           full
_refine_ls_number_parameters     266
_refine_ls_number_reflns         3796
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.108
_refine_ls_R_factor_all          0.1348
_refine_ls_R_factor_gt           0.0768
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0496P)^2^+1.8466P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1355
_refine_ls_wR_factor_ref         0.1555
_reflns_number_gt                2350
_reflns_number_total             3796
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ja804297f_si_005.cif
_cod_data_source_block           apgnhmecompound10
_cod_original_cell_volume        4306.9(10)
_cod_database_code               4108915