Synthesis and characterization of poly(LysAla3)

✍ Scribed by D. B. Wender; L. R. Treiber; H. B. Bensusan; A. G. Walton

• Book ID: 102762575
• Publisher: Wiley (John Wiley & Sons)
• Year: 1974
• Tongue: English
• Weight: 720 KB
• Volume: 13
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/bip.1974.360131002

✦ Synopsis

Abstract

The synthesis and characterization of poly(LysAla~3~) are described. The polytetrapeptide is a model for short sequences found in proelastin, and is presumably involved in desmosine or isodesmosine cross‐link formation in the native protein. Poly(LysAla~3~) is found to possess a mixture of conformations in aqueous solution dependent on molecular weight and pH. Low‐molecular‐weight (ca. 3000) material appears to be a mixture of random and extended helix at neutral pH. However, as the molecular weight is increased an increasing amount of α‐helix is observed rising to >50% for mol wt = 21,000. The α‐helical chain segments are thermally stable, melting to a mixture of extended and random forms at T~m~ = 25°C. High pH (10.5) promotes further α‐helix formation but at pH >11.0 the polypeptide becomes insoluble. The inference is that short chain segments of the peptide in elastin are unlikely to be α‐helical in the equilibrium state but may fluctuate through such a conformation.