Antibodies directed against N-terminal residues on actin do not block acto-myosin binding

Journal Article · Tue Sep 22 00:00:00 EDT 1987 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00393a018· OSTI ID:5515208

Miller, L; Kalnoski, M; Yunossi, Z; Bulinski, J C; Reisler, E

Several studies using a variety of approaches have suggested a possible role for the amino-terminal residues of skeletal muscle actin in acto-myosin interaction. In order to assess the significance of acto-S-1 contacts involving the N-terminal segment of actin, the authors have prepared polyclonal antisera against a synthetic /sup 14/C-peptide corresponding to the seven amino-terminal residues of rabbit skeletal muscle actin (..cap alpha..-N-terminal peptide). Affinity-purified immunoglobulin (Ig) G (and Fab) prepared from these antisera reacts strongly and specifically with the amino-terminal segment of both G- and F-actin but not with myosin subfragment 1 (S-1). This specificity was determined by Western blot analysis of actin and its proteolytic fragments and the inhibition of the above reactivity by the ..cap alpha..-N-terminal peptide. The ..cap alpha..-N-terminal peptide did not interact with S-1 in solution, affect S-1 and actin-activated S-1 MgATPase, or cause dissociation of the acto-S-1 complex. In separate experiments F-actin could be cosedimented with S-1 and affinity-purified IgG or Fab by using an air-driven ultracentrifuge. Densitometric analysis of sodium dodecyl sulfate/polyacrylamide gels of pellet and supernatant fractions from such experiments demonstrated the binding of both S-1 and IgG or Fab to the same F-actin protomer. The results suggest that, while the acidic N-terminal amino acids of actin may contact the myosin head, these residues cannot be the main determinants of acto-S-1 interaction.

• Research Organization: Univ. of California, Los Angeles
• OSTI ID: 5515208
• Journal Information: Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 26:19; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ACID ANHYDRASES
ACTIN
ANIMALS
ANTIBODIES
ATP-ASE
CARBON 14 COMPOUNDS
ELECTROPHORESIS
ENZYME IMMUNOASSAY
ENZYMES
GLOBULINS
HYDROLASES
IMMUNOASSAY
IMMUNOLOGY
LABELLED COMPOUNDS
MAMMALS
MOLECULAR STRUCTURE
MYOSIN
ORGANIC COMPOUNDS
PHOSPHOHYDROLASES
PROTEINS
RABBITS
VERTEBRATES