Function of tightly bound nucleotides on membrane-bound chloroplast coupling factor.

Published

Journal Article

The kinetic behavior of tightly bound nucleotides on chloroplast coupling factor from spinach was determined under phosphorylating and nonphosphorylating conditions. Chloroplast coupling factor 1 (CF1) was labeled with tightly bound radioactive ADP and/or ATP at two specific sites and reconstituted with thylakoid membranes depleted of CF1 by treatment with NaBr. The initial incorporation and dissociation of ADP from one of the sites requires light but occurs at the same rate under phosphorylating and non-phosphorylating conditions. The initial rate is considerably slower than the rate of ATP synthesis, but nucleotide exchange is very rapid during steady-state ATP synthesis. A direct correspondence between this nucleotide binding site and a site on soluble CF1 that hydrolyzes ATP was demonstrated. A second site binds MgATP very tightly; the MgATP does not dissociate during ATP synthesis nor does its presence alter the rate of ATP synthesis. This is analogous to the behavior found for soluble CF1 during ATP hydrolysis. These results demonstrate that the tight-binding nucleotide sites on soluble CF1 and membrane-bound coupling factor are essentially identical in terms of binding properties and kinetic behavior during ATP hydrolysis and synthesis.

Full Text

Duke Authors

Cited Authors

  • Leckband, D; Hammes, GG

Published Date

  • May 17, 1988

Published In

Volume / Issue

  • 27 / 10

Start / End Page

  • 3629 - 3633

PubMed ID

  • 2900652

Pubmed Central ID

  • 2900652

International Standard Serial Number (ISSN)

  • 0006-2960

Digital Object Identifier (DOI)

  • 10.1021/bi00410a016

Language

  • eng

Conference Location

  • United States