Crystal structure and stability studies of C77S HiPIP: a serine ligated [4Fe-4S] cluster.
The crystal structure of Chromatium vinosum C77S HiPIP has been determined and is compared with that of wild type. This is the first reported crystal structure of a Ser ligated [4Fe-4S] cluster and reveals a 0.11 A shortening of the Fe-O bond (relative to Fe-S), but only minor structural alterations of the overall tertiary structure. Coordination changes are corroborated by resonance Raman spectroscopy. Comparison of the crystal and solution structures for HiPIPs identifies Phe48 as the main controller of solvent access to the Fe-S cluster; however, there is no significant change in cluster solvation of the C77S mutant relative to WT HiPIP. Ser ligation ultimately results in decreased cluster stability due to increased sensitivity to proton mediated degradation.
Mansy
Sheref S
SS
Evans Laboratory of Chemistry, Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, USA.
Xiong
Yong
Y
Hemann
Craig
C
Hille
Russ
R
Sundaralingam
M
M
Cowan
J A
JA
D001426:Bacterial Proteins; D018360:Crystallography, X-Ray; D007506:Iron-Sulfur Proteins / Q000737:chemistry* / Q000302:isolation & purification; D008958:Models, Molecular; D045322:Photosynthetic Reaction Center Complex Proteins; D011487:Protein Conformation; D012694:Serine / Q000378:metabolism*; D013059:Spectrum Analysis, Raman
D001426:Bacterial Proteins; D007506:Iron-Sulfur Proteins; D045322:Photosynthetic Reaction Center Complex Proteins; C007943:high potential iron-sulfur protein; D012694:Serine