Helix and hairpin nucleation in short peptides using centrally positioned conformationally constrained dipeptide segments.
Chandrappa, Siddappa; Aravinda, Subrayashastry; Raghothama, Srinivasarao; Sonti, Rajesh; Rai, Rajkishor; Harini, Veldore V.; Shamala, Narayanaswamy; Balaram, Padmanabhan; Organic & biomolecular chemistry 10 (2012) 2815–2823; doi:10.1039/c2ob06817f

data_7152251
_publ_section_title
;
 Helix and hairpin nucleation in short peptides using centrally positioned
 conformationally constrained dipeptide segments.
;
_journal_issue                   14
_journal_name_full               'Organic &amp; biomolecular chemistry'
_journal_page_first              2815
_journal_page_last               2823
_journal_paper_doi               10.1039/c2ob06817f
_journal_volume                  10
_journal_year                    2012
_chemical_formula_moiety         'C50 H90 N8 O11 *0.5(H2O)'
_chemical_formula_sum            'C50 H90 N8 O11.5'
_chemical_formula_weight         987.30
_chemical_name_common            Boc-Leu-Val-Val-Ac6c-Leu-Val-Val-OMe
_chemical_name_systematic
;
t-Butyloxycarbonyl-leucyl-valyl-valyl-(1-aminocyclohexan-1-oyl)-valyl-
leucyl-valyl-valyl-methyl ester hemihydrate
;
_space_group_IT_number           4
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  'P 2yb'
_symmetry_space_group_name_H-M   'P 1 21 1'
_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                 97.919(3)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   10.516(3)
_cell_length_b                   27.593(4)
_cell_length_c                   21.050(3)
_cell_measurement_temperature    293(2)
_cell_volume                     6050(2)
_computing_data_collection       SMART
_computing_data_reduction        SAINT
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SnB (Weeks and Miller, 1999)'
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 0.984
_diffrn_measured_fraction_theta_max 0.984
_diffrn_measurement_device_type  'BRUKER AXS SMART APEX CCD with Mo source'
_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  0.0564
_diffrn_reflns_av_sigmaI/netI    0.0569
_diffrn_reflns_limit_h_max       13
_diffrn_reflns_limit_h_min       -13
_diffrn_reflns_limit_k_max       36
_diffrn_reflns_limit_k_min       -36
_diffrn_reflns_limit_l_max       27
_diffrn_reflns_limit_l_min       -27
_diffrn_reflns_number            71594
_diffrn_reflns_theta_full        28.06
_diffrn_reflns_theta_max         28.06
_diffrn_reflns_theta_min         1.48
_exptl_absorpt_coefficient_mu    0.077
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            'color less'
_exptl_crystal_density_diffrn    1.084
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       needle
_exptl_crystal_F_000             2152
_exptl_crystal_size_max          0.5
_exptl_crystal_size_mid          0.15
_exptl_crystal_size_min          0.15
_refine_diff_density_max         0.635
_refine_diff_density_min         -0.245
_refine_diff_density_rms         0.049
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   10(10)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   0.976
_refine_ls_hydrogen_treatment    'riding over the heavy atom'
_refine_ls_matrix_type           full
_refine_ls_number_parameters     1252
_refine_ls_number_reflns         14733
_refine_ls_number_restraints     3
_refine_ls_restrained_S_all      0.976
_refine_ls_R_factor_all          0.1204
_refine_ls_R_factor_gt           0.0644
_refine_ls_shift/su_max          3.079
_refine_ls_shift/su_mean         0.185
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.1000P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1573
_refine_ls_wR_factor_ref         0.1814
_reflns_number_gt                8010
_reflns_number_total             14733
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            c2ob06817f.txt
_cod_data_source_block           acv8
_cod_depositor_comments
;
The following automatic conversions were performed:

'_symmetry_cell_setting' value 'Monoclinic' changed to 'monoclinic'
according to /home/saulius/struct/CIF-dictionaries/cif_core.dic
dictionary named 'cif_core.dic' version 2.4.1 from 2010-06-29.

Automatic conversion script
Id: cif_fix_values 1715 2011-07-08 13:25:40Z adriana 
;
_cod_original_sg_symbol_H-M      P2(1)
_cod_original_formula_sum        'C50 H90 N8 O11.50'
_cod_database_code               7152251