Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:6.3.4.6 (urease)
 7,490 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Four microbial enzymes are known to require nickel: hydrogenase, methyl coenzyme M reductase, carbon monoxide dehydrogenase, and urease. Recent biochemical and molecular biological experiments have provided clear evidence for the existence of multiple auxiliary genes that facilitate nickel incorporation into urease and hydrogenase. Similarly, accessory factors are also likely to be required for the other two enzymes. One of the urease-related genes (ureE) encodes a cytoplasmic protein that has been purified and shown to bind nickel reversibly. We propose that the UreE protein serves as a nickel donor to urease apoprotein. A second urease-related auxiliary gene (ureG) possesses a sequence motif that is found in ATP- and GTP-binding proteins. We have shown that nickel incorporation into urease requires energy and speculate that the UreG protein may serve as an energy transducer, coupling the energy of NTP hydrolysis to metallocenter incorporation. The UreG protein is related in sequence to HypB, a protein that has been proposed to function in nickel processing in hydrogenases. Hence, the mechanisms for metallocenter biosynthesis in these two dissimilar enzymes may have evolved from a common nickel incorporation system.
 ...
PMID:Nickel enzymes in microbes. 802 91

Nickel enzymes allow microorganisms to access chemistry that can be vital for survival and virulence. In this review we highlight recent work on several systems that import nickel ions and deliver them to the active sites of these enzymes. Small molecules, in particular l-His and derivatives, may chelate nickel ions before import at TonB-dependent outer-membrane and ABC-type inner-membrane transporters. Inside the cell, nickel ions are used by maturation factors required to produce nickel enzymes such as [NiFe]-hydrogenase, urease and lactate racemase. These accessory proteins often exhibit metal selectivity and frequently include an NTP-hydrolyzing metallochaperone protein. The research described provides a deeper understanding of the processes that allow microorganisms to access nickel ions from the environment and incorporate them into nickel proteins.
 ...
PMID:Microbial nickel: cellular uptake and delivery to enzyme centers. 2821 82