1r9p

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Template:STRUCTURE 1r9p

Solution NMR Structure Of The Haemophilus Influenzae Iron-Sulfur Cluster Assembly Protein U (IscU) with Zinc Bound at the Active Site. Northeast Structural Genomics Consortium Target IR24.

Overview

IscU is a highly conserved protein that serves as the scaffold for IscS-mediated assembly of iron-sulfur ([Fe-S]) clusters. We report the NMR solution structure of monomeric Haemophilus influenzae IscU with zinc bound at the [Fe-S] cluster assembly site. The compact core of the globular structure has an alpha-beta sandwich architecture with a three-stranded antiparallel beta-sheet and four alpha-helices. A nascent helix is located N-terminal to the core structure. The zinc is ligated by three cysteine residues and one histidine residue that are located in and near conformationally dynamic loops at one end of the IscU structure. Removal of the zinc metal by chelation results in widespread loss of structure in the apo form. The zinc-bound IscU may be a good model for iron-loaded IscU and may demonstrate structural features found in the [Fe-S] cluster bound form. Structural and functional similarities, genomic context in operons containing other homologous genes, and distributions of conserved surface residues support the hypothesis that IscU protein domains are homologous (i.e. derived from a common ancestor) with the SufE/YgdK family of [Fe-S] cluster assembly proteins.

About this Structure

1R9P is a Single protein structure of sequence from Haemophilus influenzae. Full crystallographic information is available from OCA.

Reference

Solution NMR structure of the iron-sulfur cluster assembly protein U (IscU) with zinc bound at the active site., Ramelot TA, Cort JR, Goldsmith-Fischman S, Kornhaber GJ, Xiao R, Shastry R, Acton TB, Honig B, Montelione GT, Kennedy MA, J Mol Biol. 2004 Nov 19;344(2):567-83. PMID:15522305 Page seeded by OCA on Sat May 3 07:14:51 2008