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Klebsiella aerogenes UreE, a metallochaperone that delivers nickel ions during urease activation, consists of distinct 'peptide-binding' and 'metal-binding' domains and a His-rich C terminus. Deletion analyses revealed that the metal-binding domain alone is sufficient to facilitate urease activation. This domain was purified and shown to exhibit metal-binding properties similar to those of UreE lacking only the His-rich tail.

The structural genes of the Tsx proteins from Salmonella typhimurium, Klebsiella pneumoniae and Enterobacter aerogenes were cloned and sequenced for the biochemical characterization of the protein. The properties of the heterologous Tsx proteins in relation to their function in nucleoside and albicidin uptake and as bacteriophage and colicin receptors were examined. Multiple sequence alignments and structural predictions of pore-forming outer-membrane proteins were considered to develop a model for the topology of the Tsx protein within the outer membrane.

Investigation of the genomic organization of the chromosomal cps region which is necessary for capsular polysaccharide synthesis in Klebsiella pneumoniae Chedid (O1:K2) implied that the central region of the cloned 29-kb BamHI fragment is necessary for K2 capsular polysaccharide synthesis. The E. coli strains have been classified into two major groups from the genetical point of view of CPS synthesis. It is also found that the Klebsiella cps cluster requires the functions of both rmpA2 (41) and rcsB (3, 37) for the production of Klebsiella K2 CPS in E. coli K-12 (40).

The nitrogen enzyme comprises two components, of which component I catalyzes the reduction of N2 and other substrates and component II transfers electrons to dinitrogenase. Component I employs iron-molybdenum cofactor as an activizer, and is synthesized by the nif gene products. Apodinitrogenase is an oligomer that is comprised of an additional protein absent in the active dinitrogenase tetramer, and it lacks the iron-molybdenum cofactor at its active site. The protein in Klebsiella pneumoniae is a product of the nifY gene.