scholarly journals Identification of a Novel Isoform of the Chloroplast-Coupling Factor α-Subunit

1998 ◽  
Vol 116 (2) ◽  
pp. 703-708 ◽  
Author(s):  
Kent O. Burkey ◽  
James N. Mathis
Keyword(s):  
Coupling Factor ◽  
Α Subunit ◽  
Chloroplast Coupling Factor ◽  
Factor Α

Phosphate Binding to Isolated Chloroplast Coupling Factor (CF1)

1988 ◽  
Vol 43 (3-4) ◽  
pp. 213-218 ◽  
Author(s):  
Bernhard Huchzermeyer
Keyword(s):  
Atpase Activity ◽  
Binding Site ◽  
Inorganic Phosphate ◽  
Coupling Factor ◽  
Binding Domain ◽  
Atp Binding ◽  
Phosphate Binding ◽  
Chloroplast Coupling Factor ◽  
Single Binding Site ◽  
Site Binding

A single binding site for phosphate was found on isolated chloroplast coupling factor in the absence of nucleotides. In our experiments the phosphate binding site showed a Kd of 170 μᴍ. We did not observe any differences whether the ATPase activity of CF] had been activated or not. If the enzyme was incubated with [γ-32P]ATP the amount of 32P bound per CF1 depended on the pretreatment of the enzyme: In the presence of ADP no ATP or phosphate was bound to CF,. After activation of ATPase activity one mol of ATP per mol CF, was rapidly bound and hydrolyzed while there was a slowly occurring binding of another phosphate without concomitant nucleotide binding. We conclude that there are two different types of phosphate binding observed in our experiments: 1) Inorganic phosphate can be bound by one catalytic site per mol of CF1 2) The γ-phosphate of ATP is able to bind to an ATP binding domain of the enzyme if this domain can exchange substrates with the incubation medium. This ATP binding domain appears to differ from the site binding inorganic phosphate, because at least a portion of the coupling factor contains more than one labelled phosphate during our ATPase tests.

Essential role of an arginyl residue at the catalytic site(s) of chloroplast coupling factor

FEBS Letters ◽  
1977 ◽  
Vol 84 (2) ◽  
pp. 304-308 ◽  
Author(s):  
Rubén H. Vallejos ◽  
Alejandro Viale ◽  
Carlos S. Andreo
Keyword(s):  
Essential Role ◽  
Coupling Factor ◽  
Catalytic Site ◽  
Chloroplast Coupling Factor
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