Cofactor-Binding Homology Domains
of the Hybrid Cluster Proteins and the
Carbon-monoxide Dehydrogenase Nickel-Containing Chains

J.S. Garavelli, Hongzhan Huang and D.J. Miller

Protein Information Resource
National Biomedical Research Foundation
Washington, DC 20007

Poster presented at the Protein Society Meeting, August 5 - 9, 2000, San Diego, CA


The reported structure of the "putative prismane" protein from Desulfovibrio vulgaris indicates that it contains a hybrid [4Fe-2S-3O] cluster ligated by seven protein residues, three cysteines, one persulfido-cysteine, two glutamates and one histidine. The sequences of at least six other closely homologous proteins have been found, five of these from complete genomes. In three sequences, the hybrid cluster is associated with an amino terminal [4Fe-4S] cluster, while in the sequence from Escherichia coli it is associated with a [2Fe-2S] cluster. In the sequence from Methanobacterium thermoautotrophicum, it may be associated with a rubredoxin-type center. The nickel-containing chain of carbon-monoxide dehydrogenase also has a domain with some sequence similarities to the hybrid cluster proteins. The nickel-containing cluster in carbon-monoxide dehydrogenase may be structurally related to the hybrid [4Fe-2S-3O] cluster. Models have been prepared for the hybrid [4Fe-2S-3O] and the nickel hybrid clusters in the RESID Database, distributed by the Protein Information Resource (PIR) and made available on the Website at
The post-translational modifications supporting cofactor assembly in both sets of homologous proteins will be discussed.

The RESID Database is supported by NSF grant DBI-9808414.