Identification of the site of photocross-linking formed in the absence of magnesium nucleotide from SH2 (Cys-697) in myosin subfragment 1 labeled with 4'-maleimidylbenzophenone.
The site of photocross-linking between Cys-697 (SH2), prelabeled with 4'-[14C]maleimidylbenzophenone, and the 50-kDa segment of myosin S1 on irradiation in the absence of nucleotide has been determined by isolation of the 20-50-kDa adduct and subsequent tryptic proteolysis. Isolation and partial sequencing of the radioactively labeled peptide indicate that the site of cross-linking is Arg-239. This result indicates that, in the absence of nucleotide, Arg-239 resides at about 1.0 nm from SH2 and, on the basis of the recent work of Sutoh and Hiratsuka (Sutoh, K. and Hiratsuka T. (1988) Biochemistry 27, 2964-2969) places Arg-239 at no more than 1.45 nm from either Lys-184 or Lys-189 of the nucleotide-binding "glycine-rich" loop prior to the binding of nucleotide.
Agarwal
R
R
Department of Biology, Case Western Reserve University, Cleveland, Ohio 44106.
Rajasekharan
K N
KN
Burke
M
M
D000244:Adenosine Diphosphate / Q000737:chemistry / Q000378:metabolism; D000595:Amino Acid Sequence; D001577:Benzophenones; D002851:Chromatography, High Pressure Liquid; D003432:Cross-Linking Reagents; D003545:Cysteine / Q000737:chemistry* / Q000378:metabolism; D008301:Maleimides; D008969:Molecular Sequence Data; D009218:Myosins / Q000737:chemistry* / Q000378:metabolism
D001577:Benzophenones; D003432:Cross-Linking Reagents; D008301:Maleimides; D000244:Adenosine Diphosphate; C046109:benzophenone-4-maleimide; D009218:Myosins; D003545:Cysteine