The covalent maleimidobenzoyl-actin-myosin head complex: Cross-linking of the 50 kDa heavy chain region to actin subdomain-2
Abstract
We have identified the region of actin involved in the covalent coupling of maleimidobenzoyl-G-actin to the central 50 kDa segment of the myosin-S-1 heavy chain by analyzing the structure of the maleimidobenzoyl-G-actin-S-1 conjugate using selective proteolytic digestions, amino acid sequence determinations and novel cross-linking reactions between S-1 and different maleimidobenzoyl-G-actin derivatives. The cross-linking is shown to occur only on the stretch of residues 48–67 in actin subdomain-2 with Lys-50, residing on the outer part of the DNase-I-binding loop, as the most likely site of cross-linking. Because the maleimidobenzoyl-F-actin-S-1 complex undergoes the same coupling process, the data provide experimental evidence in favor of the recent model of the rigor F-actin-S-1 complex suggesting a close contact between structural elements of the lower domain of the 50 kDa fragment and the top of actin subdomain-2.
- Publication:
-
FEBS Letters
- Pub Date:
- January 1994
- DOI:
- 10.1016/0014-5793(94)00398-X
- Bibcode:
- 1994FEBSL.345..113B
- Keywords:
-
- F-actin;
- G-actin;
- Actomyosin interaction;
- Actin-myosin head cross-linking;
- Actin subdomain-2