sup 31 P and sup 1 H NMR studies of the structure of enzyme-bound substrate complexes of lobster muscle arginine kinase: Relaxation measurements with Mn(II) and Co(II)

Journal Article · Tue Nov 28 00:00:00 EST 1989 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00450a015· OSTI ID:6968946

Jarori, G K; Ray, B D; Rao, B D.N. ^[1]

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1. Indiana Univ.-Purdue Univ., Indianapolis (USA)

The paramagnetic effects of Mn(II) and Co(II) on the spin-lattice relaxation rates of {sup 31}P nuclei of ATP and ADP and of Mn(II) on the spin-lattice relaxation rate of the {delta} protons of arginine bound to arginine kinase from lobster tail muscle have been measured. Temperature variation of {sup 31}P relaxation rates in E-MnADP and E-MnATP yields activation energies ({Delta}E) in the range 6-10 kcal/mol. Thus, the {sup 31}P relaxation rates in these complexes are exchange limited and cannot provide structural information. However, the relaxation rates in E-CoADP and E-CoATP exhibit frequency dependence and {Delta}E values in the range 1-2 kcal/mol; i.e., these rates depend upon {sup 31}P-Co(II) distances. These distances were calculated to be in the range 3.2-4.5 {angstrom}, appropriate for direct coordination between Co(II) and the phosphoryl groups. The paramagnetic effect of Mn(II) on the {sup 1}H spin-lattice relaxation rate of the {delta} protons of arginine in the E-MnADP-Arg complex was also measured at three frequencies. From the frequency dependence of the relaxation rate an effective {tau}{sub C} of 0.6 ns has also been calculated, which is most likely to be the electron spin relaxation rate ({tau}{sub S1}) for Mn(II) in this complex. The distance estimated on the basis of the reciprocal sixth root of the average relaxation rate of the {delta} protons was 10.9 {plus minus} 0.3 {angstrom}.

• OSTI ID: 6968946
• Journal Information: Biochemistry; (USA), Vol. 28:24; ISSN 0006-2960
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
PHOSPHOTRANSFERASES
NUCLEAR MAGNETIC RESONANCE
ARGININE
COBALT COMPOUNDS
ENZYME ACTIVITY
LOBSTERS
MANGANESE COMPOUNDS
MUSCLES
PHOSPHORUS 31
PROTONS
SPIN-LATTICE RELAXATION
SUBSTRATES
AMINO ACIDS
ANIMALS
AQUATIC ORGANISMS
ARTHROPODS
BARYONS
CARBOXYLIC ACIDS
CRUSTACEANS
DECAPODS
ELEMENTARY PARTICLES
ENZYMES
FERMIONS
HADRONS
INVERTEBRATES
ISOTOPES
LIGHT NUCLEI
MAGNETIC RESONANCE
NUCLEI
NUCLEONS
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
PHOSPHORUS ISOTOPES
PHOSPHORUS-GROUP TRANSFERASES
RELAXATION
RESONANCE
STABLE ISOTOPES
TRANSFERASES
TRANSITION ELEMENT COMPOUNDS
550601* - Medicine- Unsealed Radionuclides in Diagnostics