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The interaction of β 2 ‐glycoprotein I domain V with chaperonin GroEL: The similarity with the domain V and membrane interaction
Author(s) -
Gozu Masayo,
Hoshino Masaru,
Higurashi Takashi,
Kato Hisao,
Goto Yuji
Publication year - 2002
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1110/ps.0216602
Subject(s) - groel , chemistry , biophysics , crystallography , nuclear magnetic resonance spectroscopy , membrane , heteronuclear molecule , biochemistry , stereochemistry , biology , escherichia coli , gene
To clarify the mechanism of interaction between chaperonin GroEL and substrate proteins, we studied the conformational changes; of the fifth domain of human β 2 ‐glycoprotein I upon binding to GroEL. The fifth domain has a large flexible loop, containing several hydrophobic residues surrounded by positively charged residues, which has been proposed to be responsible for the binding of β 2 ‐glycoprotein I to negatively charged phospholipid membranes. The reduction by dithiothreitol of the three intramolecular disulfide bonds of the fifth domain was accelerated in the presence of stoichiometric amounts of GroEL, indicating that the fifth domain was destabilized upon interaction with GroEL. To clarify the GroEL‐induced destabilization at the atomic level, we performed H/ 2 H exchange of amide protons using heteronuclear NMR spectroscopy. The presence of GroEL promoted the H/ 2 H exchange of most of the protected amide protons, suggesting that, although the flexible loop of the fifth domain is likely to be responsible for the initiation of binding to GroEL, the interaction with GroEL destabilizes the overall conformation of the fifth domain.