Ester vs. amide on folding: a case study with a 2-residue synthetic peptide.
Vijayadas, Kuruppanthara N.; Nair, Roshna V.; Gawade, Rupesh L.; Kotmale, Amol S.; Prabhakaran, Panchami; Gonnade, Rajesh G.; Puranik, Vedavadi G.; Rajamohanan, Pattuparambil R.; Sanjayan, Gangadhar J.; Organic & biomolecular chemistry 11 (2013) 8348–8356; doi:10.1039/c3ob41967c

data_7153208
_publ_section_title
;
 Ester vs. amide on folding: a case study with a 2-residue synthetic
 peptide.
;
_journal_issue                   48
_journal_name_full               'Organic &amp; biomolecular chemistry'
_journal_page_first              8348
_journal_page_last               8356
_journal_paper_doi               10.1039/c3ob41967c
_journal_volume                  11
_journal_year                    2013
_chemical_absolute_configuration syn
_chemical_formula_moiety         'C18 H24 N2 O5'
_chemical_formula_sum            'C18 H24 N2 O5'
_chemical_formula_weight         348.39
_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                   8.547(5)
_cell_length_b                   9.694(5)
_cell_length_c                   22.943(12)
_cell_measurement_reflns_used    6175
_cell_measurement_temperature    297(2)
_cell_measurement_theta_max      27.210
_cell_measurement_theta_min      2.282
_cell_volume                     1900.9(18)
_computing_cell_refinement       'SAINT (Bruker, 2003)'
_computing_data_collection       'SMART (Bruker, 2003)'
_computing_data_reduction        'SAINT (Bruker, 2003)'
_computing_molecular_graphics    'ORTEP-3 (Farrugia, 1997)'
_computing_publication_material  'SHELXTL (Bruker, 2003)'
_computing_structure_refinement  'SHELXL97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 1997)'
_diffrn_ambient_temperature      297(2)
_diffrn_measured_fraction_theta_full 0.998
_diffrn_measured_fraction_theta_max 0.998
_diffrn_measurement_device_type  'Bruker Smart Apex'
_diffrn_measurement_method       'Phi and 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  0.0905
_diffrn_reflns_av_sigmaI/netI    0.0393
_diffrn_reflns_limit_h_max       10
_diffrn_reflns_limit_h_min       -10
_diffrn_reflns_limit_k_max       11
_diffrn_reflns_limit_k_min       -11
_diffrn_reflns_limit_l_max       27
_diffrn_reflns_limit_l_min       -27
_diffrn_reflns_number            18354
_diffrn_reflns_theta_full        25.00
_diffrn_reflns_theta_max         25.00
_diffrn_reflns_theta_min         2.28
_exptl_absorpt_coefficient_mu    0.089
_exptl_absorpt_correction_T_max  0.9591
_exptl_absorpt_correction_T_min  0.8873
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'Bruker's SADABS'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.217
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       needle
_exptl_crystal_F_000             744
_exptl_crystal_size_max          1.37
_exptl_crystal_size_mid          0.54
_exptl_crystal_size_min          0.47
_refine_diff_density_max         0.160
_refine_diff_density_min         -0.233
_refine_diff_density_rms         0.055
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   -0.5(11)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.042
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     230
_refine_ls_number_reflns         3348
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.042
_refine_ls_R_factor_all          0.0490
_refine_ls_R_factor_gt           0.0479
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0887P)^2^+0.1311P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1241
_refine_ls_wR_factor_ref         0.1257
_reflns_number_gt                3213
_reflns_number_total             3348
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            c3ob41967c.txt
_cod_data_source_block           6
_cod_original_sg_symbol_H-M      P2(1)2(1)2(1)
_cod_database_code               7153208