title: Conformational changes in subdomain-2 of G-actin upon polymerization into F-actin and upon binding myosin subfragment-1.
abstract: The susceptibility of subdomain-2 of actin to different proteases has been examined, for G-actin, F-actin, G-actin-S1(A2) and F-actin-S1(A2) complexes on a comparative basis. The sites of subtilisin, alpha-chymotrypsin and trypsin attack, exposed on G-actin, are protected in F-actin, F-actin-S1(A2) as well as in the G-actin-S1(A2) complex. In contrast, a new cleavage site (Arg39-His40) for ArgC protease, which is protected in G-actin, is exposed in G-actin-S1(A2) as well as in F-actin and F-actin-S1(A2). These results are consistent with the previously proposed structural analogy between the ternary (G-actin)2S1 and the F-actin-S1 complexes, and provide information on the mechanism of S1-induced polymerization of G-actin.
authors.affiliation: Laboratoire d'Enzymologie, CNRS, Gif-sur-Yvette, France.
authors.forename: S
authors.initials: S
authors.lastname: Fievez
authors.forename: M F
authors.initials: MF
authors.lastname: Carlier
mesh_terms: D000199:Actins / Q000737:chemistry* / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D002918:Chymotrypsin / Q000737:chemistry; D008969:Molecular Sequence Data; D015879:Myosin Subfragments / Q000378:metabolism*; D011108:Polymers / Q000737:chemistry*; D011485:Protein Binding; D011487:Protein Conformation; D011817:Rabbits; D013381:Subtilisins / Q000737:chemistry; D014357:Trypsin / Q000737:chemistry
chemical_list: D000199:Actins; D015879:Myosin Subfragments; D011108:Polymers; D013381:Subtilisins; D002918:Chymotrypsin; D014357:Trypsin