Fluorine 19 NMR studies of the interaction of selectively labeled actin and myosin

Journal Article · Tue Jul 11 00:00:00 EDT 1989 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00440a028· OSTI ID:5083297

Barden, J A; Phillips, L; Cornell, B A; dos Remedios, C G ^[1]

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1. Univ. of Sydney (Australia)

Monomeric or G-actin contains five cysteine residues of which two (Cys-374 and Cys-10) can be labeled readily with 3-bromo-1,1,1-trifluoropropane and (trifluoromethyl)mercuric bromide. The {sup 19}F NMR resonances were assigned to the particular cysteines. Polymerization of the actin resulted in the fluorinated Cys-374 resonances broadening out beyond detection while the addition of myosin subfragment 1 to the F-actin also resulted in the fluorinated Cys-10 resonance becoming dramatically broad. Thus, Cys-374 appears to be close to an actin-actin binding site, and Cys-10 appears to be close to the actin-myosin binding site. (Trifluoromethyl)mercuric bromide was used to label the two reactive sulfhydryls on myosin subfragment 1, SH1 (Cys-705) and SH2 (Cys-695), which were assigned on the basis of their reactivity with N-ethylmaleimide. Addition of polymerized or F-actin to the fluorinated myosin resulted in the complete broadening of the {sup 19}F-labeled SH1 NMR resonance and the partial broadening of the nearby {sup 19}F-labeled SH2 resonance, suggesting that the actin binding site on myosin subfragment 1 involves SH1.

• OSTI ID: 5083297
• Journal Information: Biochemistry; (USA), Vol. 28:14; ISSN 0006-2960
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
ACTIN
NUCLEAR MAGNETIC RESONANCE
MUSCLES
PHYSIOLOGY
MYOSIN
CROSS-LINKING
CYSTEINE
FLUORINE 19
NMR SPECTRA
AMINO ACIDS
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
FLUORINE ISOTOPES
GLOBULINS
ISOTOPES
LIGHT NUCLEI
MAGNETIC RESONANCE
NUCLEI
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
POLYMERIZATION
PROTEINS
RESONANCE
SPECTRA
STABLE ISOTOPES
THIOLS
550601* - Medicine- Unsealed Radionuclides in Diagnostics