title: Crystal structure and stability studies of C77S HiPIP: a serine ligated [4Fe-4S] cluster.
abstract: 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.
authors.affiliation: Evans Laboratory of Chemistry, Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, USA.
authors.forename: Sheref S
authors.initials: SS
authors.lastname: Mansy
authors.forename: Yong
authors.initials: Y
authors.lastname: Xiong
authors.forename: Craig
authors.initials: C
authors.lastname: Hemann
authors.forename: Russ
authors.initials: R
authors.lastname: Hille
authors.forename: M
authors.initials: M
authors.lastname: Sundaralingam
authors.forename: J A
authors.initials: JA
authors.lastname: Cowan
mesh_terms: 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
chemical_list: D001426:Bacterial Proteins; D007506:Iron-Sulfur Proteins; D045322:Photosynthetic Reaction Center Complex Proteins; C007943:high potential iron-sulfur protein; D012694:Serine