title: Intramolecular interaction in the tail of Acanthamoeba myosin IC between the SH3 domain and a putative pleckstrin homology domain.
abstract: The 466-aa tail of the heavy chain of Acanthamoeba myosin IC (AMIC) comprises an N-terminal 220-residue basic region (BR) followed by a 56-residue Gly/Pro/Ala-rich region (GPA1), a 55-residue Src homology 3 (SH3) domain, and a C-terminal 135-residue Gly/Pro/Ala-rich region (GPA2). Cryo-electron microscopy of AMIC had shown previously that the AMIC tail is folded back on itself, suggesting the possibility of interactions between its N- and C-terminal regions. We now show specific differences between the NMR spectrum of bacterially expressed full-length tail and the sum of the spectra of individually expressed BR and GPA1-SH3-GPA2 (GSG) regions. These results are indicative of interactions between the two subdomains in the full-length tail. From the NMR data, we could assign many of the residues in BR and GSG that are involved in these interactions. By combining homology modeling with the NMR data, we identify a putative pleckstrin homology (PH) domain within BR, and show that the PH domain interacts with the SH3 domain.
authors.affiliation: Laboratory of Biophysical Chemistry and Laboratory of Cell Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Kae-Jung
authors.initials: KJ
authors.lastname: Hwang
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Mahmoodian
authors.forename: James A
authors.initials: JA
authors.lastname: Ferretti
authors.forename: Edward D
authors.initials: ED
authors.lastname: Korn
authors.forename: James M
authors.initials: JM
authors.lastname: Gruschus
mesh_terms: D000048:Acanthamoeba / Q000737:chemistry* / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D001798:Blood Proteins / Q000737:chemistry*; D017124:Conserved Sequence; D008958:Models, Molecular; D008969:Molecular Sequence Data; D024461:Myosin Type I / Q000737:chemistry* / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D019906:Nuclear Magnetic Resonance, Biomolecular; D010750:Phosphoproteins / Q000737:chemistry*; D016415:Sequence Alignment; D040681:Structural Homology, Protein; D018909:src Homology Domains
chemical_list: D001798:Blood Proteins; D010750:Phosphoproteins; C039077:platelet protein P47; D024461:Myosin Type I