Structural model of the regulatory domain of smooth muscle heavy meromyosin

Jan L Wahlstrom; M Allen Randall, Jr; J David Lawson; Derek E Lyons; William F Siems; Greg J Crouch; Regina Barr; Kevin C Facemyer; Christine R Cremo

doi:10.1074/jbc.M206963200

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Structural model of the regulatory domain of smooth muscle heavy meromyosin

Journal article

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Peer reviewed

Structural model of the regulatory domain of smooth muscle heavy meromyosin

Jan L Wahlstrom, M Allen Randall, Jr, J David Lawson, Derek E Lyons, William F Siems, Greg J Crouch, Regina Barr, Kevin C Facemyer and Christine R Cremo

The Journal of biological chemistry, Vol.278(7), pp.5123-5131

02/14/2003

DOI: https://doi.org/10.1074/jbc.M206963200

Handle:

https://hdl.handle.net/2376/115177

PMID: 12446732

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Abstract

Protein Structure, Tertiary

Amino Acid Sequence

Cross-Linking Reagents

Peptide Fragments

Phosphorylation

Myosin Subfragments - metabolism

Models, Molecular

Molecular Sequence Data

Myosin Subfragments - chemistry

Structure-Activity Relationship

Muscle, Smooth - metabolism

Animals

Chickens

The goal of this study was to provide structural information about the regulatory domains of double-headed smooth muscle heavy meromyosin, including the N terminus of the regulatory light chain, in both the phosphorylated and unphosphorylated states. We extended our previous photo-cross-linking studies (Wu, X., Clack, B. A., Zhi, G., Stull, J. T., and Cremo, C. R. (1999) J. Biol. Chem. 274, 20328-20335) to determine regions of the regulatory light chain that are cross-linked by a cross-linker attached to Cys(108) on the partner regulatory light chain. For this purpose, we have synthesized two new biotinylated sulfhydryl reactive photo-cross-linking reagents, benzophenone, 4-(N-iodoacetamido)-4'-(N-biotinylamido) and benzophenone, 4-(N-maleimido)-4'-(N-biotinylamido). Cross-linked peptides were purified by avidin affinity chromatography and characterized by Edman sequencing and mass spectrometry. Labeled Cys(108) from one regulatory light chain cross-linked to (71)GMMSEAPGPIN(81), a loop in the N-terminal half of the regulatory light chain, and to (4)RAKAKTTKKRPQR(16), a region for which there is no atomic resolution data. Both cross-links were to the partner regulatory light chain and occurred in unphosphorylated but not phosphorylated heavy meromyosin. Using these data, data from our previous study, and atomic coordinates from various myosin isoforms, we have constructed a structural model of the regulatory domain in an unphosphorylated double-headed molecule that predicts the general location of the N terminus. The implications for the structural basis of the phosphorylation-mediated regulatory mechanism are discussed.

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Title: Structural model of the regulatory domain of smooth muscle heavy meromyosin
Creators: Jan L Wahlstrom - Department of Biochemistry, University of Nevada, Reno, Nevada 89557, USA
M Allen Randall, Jr
J David Lawson
Derek E Lyons
William F Siems
Greg J Crouch
Regina Barr
Kevin C Facemyer
Christine R Cremo
Publication Details: The Journal of biological chemistry, Vol.278(7), pp.5123-5131
Academic Unit: Chemistry, Department of
Publisher: United States
Identifiers: 99900548122601842
Language: English
Resource Type: Journal article