Spin-echo sup 1 H NMR studies of differential mobility in gizzard myosin and its subfragments

Journal Article · Sat Dec 01 04:00:00 EST 1990 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00500a020· OSTI ID:5735288

Sommervile, L E ^[1]; Henry, G D; Sykes, B D ^[2]; Harshorne, D J ^[3]

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1. St. Lawrence Univ., Canton, NY (USA)
2. Univ. of Alberta, Edmonton (Canada)
3. Univ. of Arizona, Tucson (USA)

The unexpectedly narrow resonances in the {sup 1}H NMR spectra of gizzard myosin, heavy meromyosin, and subfragment 1 were examined by spin-echo NMR spectroscopy. These resonances originated predominantly in the myosin heads, or subfragment 1 units. Smooth muscle myosin undergoes a dramatic change in hydrodynamic properties and can exist either as a folded (10S) or as an extended (6S) species. Factors that influence this transition, namely, ionic strength and phosphorylation (or thiophosphorylation), were varied in the NMR experiments. T{sub 2} relaxation experiments on dephosphorylated myosin indicated several components of different relaxation times that were not influenced by changes in ionic strength. The experiments focused on the components with longer relaxation times, i.e., corresponding to nuclei with more mobility, and these were observed selectively in a spin-echo experiment. With dephosphorylated myosin and HMM, increases in ionic strength caused an increased intensity in several of the narrower resonances. The ionic strength dependence of these changes paralleled that for the 10S and 6S transition. With thiophosphorylated myosin and HMM, changes in ionic strength also influenced the intensities of the narrower resonances, and in addition changes in the {sup 1}H NMR spectrum due to thiophosphorylation were observed. These results suggest that a fraction of the {sup 1}H resonances in smooth muscle myosin and its fragments originates from both aliphatic and aromatic residues of increased mobility compared to the mobility expected from hydrodynamic properties of these proteins.

• OSTI ID: 5735288
• Journal Information: Biochemistry; (USA), Journal Name: Biochemistry; (USA) Vol. 29:48; ISSN 0006-2960; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
62 RADIOLOGY AND NUCLEAR MEDICINE
BARYONS
CHEMICAL REACTIONS
ELEMENTARY PARTICLES
FERMIONS
GLOBULINS
HADRONS
MAGNETIC RESONANCE
MUSCLES
MYOSIN
NUCLEAR MAGNETIC RESONANCE
NUCLEONS
ORGANIC COMPOUNDS
PHOSPHORYLATION
PHYSIOLOGY
PROTEINS
PROTONS
RELAXATION
RESONANCE
SPIN ECHO
VISCOSITY