title: Peptides containing the sulfonamide transition-state isostere: synthesis and structure of N-acetyl-tauryl-L-proline methylamide.
abstract: The structure of the sulfonamide isostere-containing peptide N-acetyl-tauryl-proline methylamide 4 was compared to information on the structure of the peptide N-acetyl-beta-alanyl-proline methylamide 6. NMR measurements of the beta-alanine containing peptide 6 showed the presence of two conformations due to cis/trans isomerism of the beta-Ala-Pro amide bond, whereas the sulfonamide-containing peptide 4 appeared in only one conformation. The crystal structure of N-acetyl-tauryl-proline methylamide 4 gave additional evidence for the absence of cis/trans isomerism. The crystals are orthorhombic, space group P2(1)2(1)2(1), Z = 4, F(000) = 592, a = 7.5919(3), b = 10.3822(2), c = 17.1908(7) A, V = 1354.99(8) A3, Dx = 1.359 g cm-3. The oxygen atoms connected to the sulfur take positions similar to both the cis and trans positions of the carbonyl oxygen of an amide. Consequently the tauryl part is placed perpendicular to the proline alpha-C-C(O) bond, giving it an extended conformation in contrast to the cis/trans isomers of N-acetyl-beta-alanyl-proline methylamide 6.
authors.affiliation: Department of Organic Chemistry, Gorlaeus Laboratories, University of Leiden, The Netherlands.
authors.forename: W J
authors.initials: WJ
authors.lastname: Moree
authors.forename: A
authors.initials: A
authors.lastname: Schouten
authors.forename: J
authors.initials: J
authors.lastname: Kroon
authors.forename: R M
authors.initials: RM
authors.lastname: Liskamp
mesh_terms: D018360:Crystallography, X-Ray; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D015394:Molecular Structure; D010455:Peptides / Q000138:chemical synthesis* / Q000737:chemistry; D011392:Proline / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry; D013237:Stereoisomerism; D013654:Taurine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry
chemical_list: C095954:N-acetyl-tauryl-proline methylamide; D010455:Peptides; D013654:Taurine; D011392:Proline