Circular dichroism studies of the conformation of synthetic peptides in the carboxyl-terminal region of cytochrome c

Biochemistry ◽  
1973 ◽  
Vol 12 (17) ◽  
pp. 3166-3169 ◽  
Author(s):  
Shosuke Kawanishi ◽  
Seiyo Sano
1993 ◽  
Vol 115 (21) ◽  
pp. 9854-9855 ◽  
Author(s):  
Eefei Chen ◽  
William Parker ◽  
James W. Lewis ◽  
Pill Soon Song ◽  
David S. Kliger

1998 ◽  
Vol 76 (5) ◽  
pp. 837-842 ◽  
Author(s):  
Daniel Gebreselassie ◽  
Krishna Rajarathnam ◽  
Larry Fliegel

The Na+/H+ exchanger is a pH regulatory protein that is responsible for removal of excess intracellular protons in exchange for extracellular Na+. It is a plasma membrane protein with a large cytoplasmic carboxyl terminal domain that regulates activity of the membrane domain. We overexpressed and purified the cytoplasmic domain that was produced in Escherichia coli. This region (516-815 amino acids) was under control of the tac promoter from the plasmid pGEX-KG and was fused with glutathione S-transferase. Upon induction, the fusion protein was principally found in inclusion bodies. Purified inclusion bodies were solubilized and fractionated using preparative SDS polyacrylamide gel electrophoresis. To obtain free Na+/H+ exchanger protein the fusion protein was dialyzed against cleavage buffer and cleaved at the thrombin cleavage site between glutathione S-transferase and the Na+/H+ exchanger domain. Free Na+/H+ exchanger protein was obtained by rerunning the sample on preparative gel electrophoresis. The final yield of the purified protein was 2.15 mg protein/L of cell culture. After exhaustive dialysis the secondary structure of the purified protein was assessed using circular dichroism spectroscopy. The results indicated that the protein was 35% alpha-helix, 17% beta-turn, and 48% random coil. They suggest that the cytoplasmic domain is structured and some regions may be compact in nature.Key words: Na+/H+ exchanger, pH regulation, membrane protein, circular dichroism.


1982 ◽  
Vol 207 (1) ◽  
pp. 167-170 ◽  
Author(s):  
A J Thomson ◽  
D G Englinton ◽  
B C Hill ◽  
C Greenwood

The magnetic-circular-dichroism (m.c.d.) spectra of oxidized ‘resting’ bovine cytochrome c oxidase and the cyanide-inhibited form are reported at 5.15 T and at 4.2 K along with m.c.d. magnetization curves plotted at selected wavelengths. In both spectra there are features at 790nm and 1564nm due to Cua and haem a respectively, the e.p.r.-detectable components of the enzyme. There is a new peak at 1946nm only in the spectrum of the cyanide-inhibited enzyme. Arguments are advanced that assign this to low-spin ferric haem a3 bridged to Cua3, thereby forming a ferromagnetically coupled pair of metal ions.


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