Presence of Ferric Hydroxide Clusters in Mutants of Haemophilus influenzae Ferric Ion-Binding Protein A

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• 作者：Stephen R. Shouldice ; Robert J. Skene ; Douglas R. Dougan ; Duncan E. McRee ; Leslie W. Tari ; and Anthony B. Schryvers
• 刊名：Biochemistry
• 出版年：2003
• 出版时间：October 21, 2003
• 年：2003
• 卷：42
• 期：41
• 页码：11908 - 11914
• 全文大小：707K
• 年卷期：v.42,no.41(October 21, 2003)
• ISSN：1520-4995

文摘

The periplasmic iron binding protein plays an essential role in the iron uptake pathway ofGram-negative pathogenic bacteria from the Pasteurellaceae and Neisseriaceae families and is critical forsurvival of these pathogens within the host. In this study, we report the crystal structures of two mutantforms of ferric ion-binding protein A (FbpA) from Haemophilus influenzae with bound multinuclear oxo-metal clusters. Crystals of site-directed mutants in the metal or anion binding ligands contain protein inthe open conformation, and two mutant FbpAs, H9A and N175L, contain different cluster arrangementsin the iron-binding pocket. The iron clusters are anchored by binding to the two tyrosine ligands (Tyr195and Tyr196) positioned at the vertex of the iron-binding pocket but are not coordinated by the other metalbinding ligands. Our results suggest that the metal clusters may have formed in situ, suggesting that themutant FbpAs may serve as a simple model for protein-mediated mineralization.