J. Biol. Chem., Vol. 263, Issue 28, 14115-14121, 10, 1988
The actin-myosin subfragment-1 complex stabilized by phenyldiglyoxal
A Bonet, E Audemard and D Mornet
Centre de Recherches de Biochimie Macromoleculaire du Centre National de la Recherche Scientifique, Institut National de la Sante et de la Recherche Medicale, U 249, Universite de Montpellier, France.
Nuclear magnetic resonance studies have revealed the importance of arginine
residues in the actin-myosin interface (Moir, A. J. G., and Levine, B. A.
(1986) J. Inorg. Chem. 27, 271-278). In the present study, we tested the
involvement of these residues in the rigor complex between actin and
subfragment-1 (S1) by chemical cross-linking experiments using
phenyldiglyoxal. Two kinds of linkages were observed, one within the S1
heavy chain itself (120-kDa product) and the other between actin and the S1
heavy chain (200-kDa product). The phenyldiglyoxal had an effect similar to
that of phenylglyoxal on S1 ATPase activities. We also show that
phenyldiglyoxal (of 0.6-0.8 nm arm length) cross-links an arginine residue
of the 50-kDa domain to one in the 20-kDa domain of the S1 heavy chain in
the absence of actin or to an arginine in actin when actin is present. The
presence of Mg2+, adenosine 5'-diphosphate or 5'-adenylyl imidodiphosphate
suppressed the intermolecular linkage with actin, and favored the
intramolecular cross- link, (i.e. between 50-kDa and 20-kDa fragments). We
propose that the same arginyl residue in the N-terminal part of the 50-kDa
domain can be cross-linked to a nearby arginine in either the 20-kDa domain
or the actin molecule. In accordance with the amino acid sequence of each
protein this also implies that the actin-myosin interaction involves
arginine residues located either after residue 28 of the N-terminal part of
actin, since this actin region is devoid of arginine residues, or in the
N-terminal portion of the 50-kDa domain, i.e. between residues 239 and 455.
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