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_7152252
_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         'C58 H90 N8 O11'
_chemical_formula_sum            'C58 H90 N8 O11'
_chemical_formula_weight         1075.38
_chemical_name_common            Boc-Leu-Phe-Val-Ac6c-Val-Leu-Phe-Val-OMe
_chemical_name_systematic
;
t-Butyloxycarbonyl-leucyl-phenylalanyl-valyl-(1-aminocyclohexan-1-oyl)-valyl-
leucyl-phenylalanyl-valyl-methyl ester
;
_space_group_IT_number           19
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  'P 2ac 2ab'
_symmetry_space_group_name_H-M   'P 21 21 21'
_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            4
_cell_length_a                   11.312(4)
_cell_length_b                   19.868(6)
_cell_length_c                   28.099(9)
_cell_measurement_temperature    293(2)
_cell_volume                     6315(4)
_computing_data_collection       SMART
_computing_data_reduction        SAINT
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXD (Schneider and Sheldrick, 2002)'
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 0.953
_diffrn_measured_fraction_theta_max 0.953
_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  0.1495
_diffrn_reflns_av_sigmaI/netI    0.0814
_diffrn_reflns_limit_h_max       14
_diffrn_reflns_limit_h_min       -14
_diffrn_reflns_limit_k_max       24
_diffrn_reflns_limit_k_min       -25
_diffrn_reflns_limit_l_max       35
_diffrn_reflns_limit_l_min       -32
_diffrn_reflns_number            62458
_diffrn_reflns_theta_full        26.89
_diffrn_reflns_theta_max         26.89
_diffrn_reflns_theta_min         1.26
_exptl_absorpt_coefficient_mu    0.078
_exptl_crystal_colour            'color less'
_exptl_crystal_density_diffrn    1.131
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       rod
_exptl_crystal_F_000             2328
_exptl_crystal_size_max          0.5
_exptl_crystal_size_mid          0.3
_exptl_crystal_size_min          0.2
_refine_diff_density_max         0.393
_refine_diff_density_min         -0.237
_refine_diff_density_rms         0.051
_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   1.075
_refine_ls_hydrogen_treatment    'riding over the heavy atom'
_refine_ls_matrix_type           full
_refine_ls_number_parameters     694
_refine_ls_number_reflns         7153
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.075
_refine_ls_R_factor_all          0.1279
_refine_ls_R_factor_gt           0.0767
_refine_ls_shift/su_max          0.363
_refine_ls_shift/su_mean         0.044
_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          0.1619
_refine_ls_wR_factor_ref         0.1855
_reflns_number_gt                4488
_reflns_number_total             7153
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            c2ob06817f.txt
_cod_data_source_block           fac8
_cod_depositor_comments
;
The following automatic conversions were performed:

'_symmetry_cell_setting' value 'Orthorhombic' changed to
'orthorhombic' 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_cell_volume        6315(3)
_cod_original_sg_symbol_H-M      P2(1)2(1)2(1)
_cod_database_code               7152252