Effect of hydrophilic polymer conjugation on heat-induced conformational changes in a protein

Ji Hun Seo, Ryosuke Matsuno, Yan Lee, Tomohiro Konno, Madoka Takai, Kazuhiko Ishihara

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

End-functional 2-methacryloyloxyethyl phosphorylcholine (MPC) co-polymers containing two different monomer units, 2-hydroxyethyl methacrylate (HEMA) and n-butyl methacrylate (BMA), with varying hydrophilicities were synthesized to investigate the effect of the conjugated hydrophilic polymer on the heat-induced conformational changes of a protein. MPC co-polymer-conjugated proteins containing the HEMA unit (PMH) could withstand thermal conformational changes better than those containing the more hydrophobic BMA unit (PMB). The changes in protein tertiary structures were estimated via the excitation of tryptophan. PMH-conjugated proteins could withstand heat-induced intensity changes better than the PMB-conjugated proteins. Thus, hydrophilic units in the conjugated polymer are probably essential in suppressing the heat-induced conformational changes of a protein. The changes in secondary and tertiary structures of poly(MPC)-(PMPC) and poly(HEMA) (PHEMA)-conjugated proteins were compared to validate the effect of MPC units on heat-induced conformational change. Although the thermally induced conformational changes in the secondary and tertiary structures of PHEMA-conjugated proteins were partially suppressed, the effect on PMPC-conjugated proteins was much greater, with significant conformational preservation. This is due to the specific hydration state of the hydrophilic PMPC chain, which reduces interaction between the protein molecules.

Original languageEnglish
Pages (from-to)1477-1484
Number of pages8
JournalActa Biomaterialia
Volume7
Issue number4
DOIs
Publication statusPublished - 2011 Apr
Externally publishedYes

Keywords

  • Bioconjugation
  • Bovine serum albumin
  • Circular dichroism
  • Phospholipid polymer
  • Protein conformation

ASJC Scopus subject areas

  • Biotechnology
  • Biomaterials
  • Biochemistry
  • Biomedical Engineering
  • Molecular Biology

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