Maleimidobenzoyl-G-actin: Structural properties and interaction with skeletal myosin subfragment-1

Journal Article · Tue Sep 25 00:00:00 EDT 1990 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00490a028· OSTI ID:5770172

Bettache, N; Bertrand, R; Kassab, R ^[1]

---

1. Universite de Montpellier (France)

The authors have investigated various structural and interaction properties of maleimidobenzoyl-G-actin (MBS-actin), a new, internally cross-linked G-actin derivative that does not exhibit, at moderate protein concentration, the salt-and myosin subfragment 1 (S-1)--induced polymerizations of G-actin and reacts reversibly and covalently in solution with S-1 at or near the F-actin binding region of the heavy chain. The far-ultraviolet CD spectrum and {alpha}-helix content of the MBS-actin were identical with those displayed by native G-actin. {sup 45}Ca{sup 2+} measurements showed the same content of tightly bound Ca{sup 2+} in MBS-actin as in G-actin and the EDTA treatment of the modified protein promoted the same red shift of the intrinsic fluorescence spectrum as observed with native G-actin. Incubation of concentrated MBS-actin solutions with 100 mM KCl+5 mM MgCl{sub 2} led to the polymerization of the actin derivative when the critical monomer concentration reached 1.6mg/mL, at 25{degree}C, pH 8.0. The MBS-F-actin formed activated the Mg{sup 2+}-ATPase of S-1 to the same extent as native F-actin. The MBS-G-actin exhibited a DNase I inhibitor activity very close to that found with native G-actin and was to be at all affected by its specific covalent conjugation to S-1. This finding led them to isolate, for the first time, by gel filtration, a ternary complex comprising DNase I tightly bound to MBS-actin cross-linked to the S-1 heavy chain, demonstrating that S-1 and DNase I bind at distinct sites on G-actin. Collectively, the data illustrate further the nativeness of the MBS-G-actin and its potential use in solution studies of the actin-myosin head interactions.

• OSTI ID: 5770172
• Journal Information: Biochemistry; (USA), Vol. 29:38; ISSN 0006-2960
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
ACTIN
STRUCTURE-ACTIVITY RELATIONSHIPS
CALCIUM 45
DNA-ASE
ELECTROPHORESIS
EMISSION SPECTRA
FLUORESCENCE SPECTROSCOPY
MAGNETIC CIRCULAR DICHROISM
MYOSIN
PROTEIN ENGINEERING
TRACER TECHNIQUES
ALKALINE EARTH ISOTOPES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CALCIUM ISOTOPES
DAYS LIVING RADIOISOTOPES
DICHROISM
EMISSION SPECTROSCOPY
ENZYMES
ESTERASES
EVEN-ODD NUCLEI
GLOBULINS
HYDROLASES
INTERMEDIATE MASS NUCLEI
ISOTOPE APPLICATIONS
ISOTOPES
NUCLEI
ORGANIC COMPOUNDS
PHOSPHODIESTERASES
PROTEINS
RADIOISOTOPES
SPECTRA
SPECTROSCOPY
550201* - Biochemistry- Tracer Techniques