Effects of potassium on lipid-protein interactions in light sarcoplasmic reticulum

Journal Article · Mon Jan 15 23:00:00 EST 1990 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00454a016· OSTI ID:6698069

Selinsky, B S; Yeagle, P L ^[1]

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1. State Univ. of New York, Buffalo (USA)

This study shows the effect of K{sup +} on phospholipid-protein interactions in light sarcoplasmic reticulum (LSR) as measured by {sup 31}P NMR. In the presence of 110 mM K{sup +}, a substantial effect of the membrane protein on the behavior of the phospholipids was detected. Subtracting the spectrum of the LSR lipid extract from the spectrum of the intact LSR membrane produced a difference spectrum of much greater breadth than the normal phospholipid bilayer powder pattern. This powder pattern is indicative of a phospholipid domain considerably more motionally restricted than the phospholipids in a normal phospholipid bilayer. The apparent axially symmetric powder pattern is consistent with axial diffusion. In a reconstituted membrane containing the calcium pump protein at a lipid/protein ratio much less than in the light sarcoplasmic reticulum, the broad component was more prominent. The relative resonance intensity of the broad component appeared to be proportional to the lipid/protein ratio of the membrane. In 10 mM K{sup +}, no broad powder pattern is observed in the corresponding difference spectrum. Thus, in the absence of potassium, the membrane protein has much less influence on the phospholipid of the membrane, as measured by {sup 31}P NMR. In addition to the effects of K{sup +} on the membrane structure of the sarcoplasmic reticulum, K{sup +} modulated the function of the calcium pump. The rate of calcium-dependent ATP hydrolysis increased in light sarcoplasmic reticulum when (K{sup +}) increased from 10 to 110 mM. The rate of calcium transport was also stimulated by an increase in K{sup +}.

• OSTI ID: 6698069
• Journal Information: Biochemistry; (USA), Journal Name: Biochemistry; (USA) Vol. 29:2; 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
ALKALI METAL COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
ATP
CALCIUM COMPOUNDS
CATIONS
CELL CONSTITUENTS
CHARGED PARTICLES
CHEMICAL REACTIONS
CROSS-LINKING
ENDOPLASMIC RETICULUM
ESTERS
IONS
ISOTOPES
LIGHT NUCLEI
LIPIDS
MAGNETIC RESONANCE
MEMBRANES
MOLECULAR STRUCTURE
NUCLEAR MAGNETIC RESONANCE
NUCLEI
NUCLEOTIDES
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
ORGANOIDS
PHOSPHOLIPIDS
PHOSPHORUS 31
PHOSPHORUS ISOTOPES
POLYMERIZATION
POTASSIUM COMPOUNDS
PROTEINS
RESONANCE
SARCOPLASMIC RETICULUM
STABLE ISOTOPES