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Evidence that the N-terminal region of A1-light chain of myosin interacts directly with the C-terminal region of actin.
- Source :
-
European Journal of Biochemistry . 4/1/87, Vol. 164 Issue 1, p259-266. 8p. - Publication Year :
- 1987
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Abstract
- Earlier 1H-NMR experiments on the myosin subfragment-1 (S1) light chain isoenzymes from rabbit fast muscle, containing either the A1 or the A2 alkali light chains [S1(A1) or S1(A2)], have shown that the 41-residue N-terminal extension of A1, rich in proline, alanine and lysine residues, is freely mobile in solution but that this mobility is constrained in the acto-S1(A1) complex [Prince et al. (1981) Eur. J. Biochem. 121,213–219]. It is now established that this N-terminal region of the A l-light chain interacts directly with the C-terminal region of actin in the acto-Sl (A1) complex. This was shown by covalently labelling the Cys-374 residue of actin with a spin-label and observing the enhanced relaxation this paramagnetic centre induced in the 1H-NMR spectrum of S1(A1). In particular, the signal arising from the -N+ (CH3)3 protons of α-N-trimethylalanine (Me3Ala) were monitored as this residue is uniquely sited at the N-terminus of the A1 light chain [Henry et al. (1982) FEBS Lett. 144, 11 — 15]. Experiments using complexes of actin with either the N-terminal 37-residue peptide of A1, S1 (A1) or heavy meromyosin indicate that the N-terminal region of A1 is binding in a similar manner to actin in each case, with the N-terminal Me3A1a residue within 1.5 nm of the spin label introduced to Cys-374 of actin. A similar strategy was adopted to show that the Me3Ala residue can also be found close (<1.5 rim) to the fast-reacting SH1 thiol group on the S1 heavy chain. These data, together with published work, have been used to suggest a possible organisation for the polypeptide chains in the myosin head. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00142956
- Volume :
- 164
- Issue :
- 1
- Database :
- Academic Search Index
- Journal :
- European Journal of Biochemistry
- Publication Type :
- Academic Journal
- Accession number :
- 13669738
- Full Text :
- https://doi.org/10.1111/j.1432-1033.1987.tb11019.x