ISSN:
1432-1017
Keywords:
β-bend
;
crystal structure
;
hydrogen bond
;
infrared spectroscopy
;
NMR spectroscopy
;
peptide conformation
;
X-ray diffraction
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Physics
Notes:
Abstract IR, 1H-NMR and X-ray experiments have been carried out on dipeptides with the Pro-Asp and Pro-Asn sequences protected on both ends by amide groups. The Pro-Asp dipeptide was investigated for the carboxylic, methyl ester and carboxylate forms of the Asp residue. In solution, all dipeptides are found to accommodate almost exclusively the βI-turn conformation stabilized by an interaction between the Asp or Asn-NH and CγO bonds. The βI-turn percentage roughly parallels the basicity of the Asp or Asn side substituent, and decreases from Asp- to Asn, and to Asp or Asp (OMe). The βI-turn, stabilized by the interaction involving the Asp-CγO site, is retained in the crystal structure of the Pro-Asp(OMe) dipeptide. The Pro-Asp and Pro-Asn dipeptides assume a βII-turn conformation in the solid state and the polar Asp or Asn side-groups are involved in a complex network of intermolecular interactions.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00260402
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