Conformation of membrane-bound proteins revealed by vacuum-ultraviolet circular-dichroism and linear-dichroism spectroscopy

Koichi Matsuo, Yasuyuki Maki, Hirofumi Namatame, Masaki Taniguchi, Kunihiko Gekko

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)

Abstract

Knowledge of the conformations of a water-soluble protein bound to a membrane is important for understanding the membrane-interaction mechanisms and the membrane-mediated functions of the protein. In this study we applied vacuum-ultraviolet circular-dichroism (VUVCD) and linear-dichroism (LD) spectroscopy to analyze the conformations of α-lactalbumin (LA), thioredoxin (Trx), and β-lactoglobulin (LG) bound to phosphatidylglycerol liposomes. The VUVCD analysis coupled with a neural-network analysis showed that these three proteins have characteristic helix-rich conformations involving several helical segments, of which two amphiphilic or hydrophobic segments take part in interactions with the liposome. The LD analysis predicted the average orientations of these helix segments on the liposome: two amphiphilic helices parallel to the liposome surface for LA, two hydrophobic helices perpendicular to the liposome surface for Trx, and a hydrophobic helix perpendicular to and an amphiphilic helix parallel to the liposome surface for LG. This sequence-level information about the secondary structures and orientations was used to formulate interaction models of the three proteins at the membrane surface. This study demonstrates the validity of a combination of VUVCD and LD spectroscopy in conformational analyses of membrane-binding proteins, which are difficult targets for X-ray crystallography and nuclear magnetic resonance spectroscopy. Proteins 2016; 84:349-359.

Original languageEnglish
Pages (from-to)349-359
Number of pages11
JournalProteins: Structure, Function and Bioinformatics
Volume84
Issue number3
DOIs
Publication statusPublished - Mar 1 2016
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Structural Biology
  • Biochemistry
  • Molecular Biology

Fingerprint Dive into the research topics of 'Conformation of membrane-bound proteins revealed by vacuum-ultraviolet circular-dichroism and linear-dichroism spectroscopy'. Together they form a unique fingerprint.

Cite this