Protein hybrid cluster

FIGURE 12.3 S = 9/2 EPR of Desulfovibrio desulfuricans hybrid cluster protein. Note the weak low-field peak with g > 14 and the relatively strong intensities in the g 5.4 and g 6.4 regions, which are all characteristics of the S = 9/2 system. 

An interesting new tetranuclear iron hybrid cluster protein (HCP) has been observed and characterized from two sulfate reducing bacteria. Combined X-ray diffraction and EPR data showed that it contains both oxygen and sulfur bridges between the iron ions. The nature of the cluster was found to be independent of the presence or absence of oxygen in the sample preparation.247... 

PFO puruvate ferredoxin oxidoreductase, HCP hybrid cluster protein, PNO... 

PFO puruvateiferredoxin oxidoreductase, HCP hybrid cluster protein, PNO pyruvate NADH oxidoreductase, Nbp35 P-loop NTPase, Nar/Narf hydrogenase-like protein, Rli ATP-binding cassette protein... 

Hackstein JHP, Akhmanova A, Boxma B, Harhangi HR, Voncken FGJ (1999) Hydrogenosomes eukaryotic adaptations to anaerobic environments. Trends Microbiol 7 441-447 Han KL, Yong TS, Ryu JS, Hwang UW, Park SJ (2004) Identification of the hybrid cluster protein, HCP, from amitochondriate eukaryotes and its phylogenetic implications. J Microbiol Biotechnol 14 134-139... 

Cluster 2 appears to be unique among Fe-S-containing proteins whose structures have so far been determined, emd it has been termed the hybrid cluster (6) because of its diverse chemical nature. Figure 14 is a schematic drawing of the cluster as interpreted from the final electron density synthesis and the structure refinement. The cluster contains both oxygen and sulfur bridges, and X represents a site whose precise nature has not been determined, but which may contain a partially occupied and/or disordered substrate molecule (see Section III,B,3,b). The environments of the four iron atoms can be described as follows. 

Figure 5 A sketch of the structure of the hybrid cluster in the prismane protein. The approximate core structure is [4Fe-2S-20]. Cys406 carries a persulfido sulfur. X is an unidentified bridge of low occupancy in the crystal structure.

Ferran, E. A. Pflugfelder, B. (1993). A hybrid method to cluster protein sequences based on statistics and artificial neural networks. ComputAppl Biosci 9,671-80. 

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