Ecology and biotechnology of the genus Shewanella.

The shewanellae are aquatic microorganisms with worldwide distribution. Their hallmark features include unparalleled respiratory diversity and the capacity to thrive at low temperatures. As a genus the shewanellae are physiologically diverse, and this review provides an overview of the varied roles they serve in the environment and describes what is known about how they might survive in such extreme and harsh environments.

A suppressor analysis of residues involved in cation transport in the lactose permease: identification of a coupling sensor.

Four amino acids critical for lactose permease function were altered using site-directed mutagenesis. The resulting Quad mutant (E269Q/R302L/H322Q/E325Q) was expressed at 60% of wild-type levels but found to have negligible transport activity. The Quad mutant was used as a parental strain to isolate suppressors that regained the ability to ferment the alpha-galactoside melibiose.

Manganese-substituted carbonic anhydrase as a new peroxidase.

Carbonic anhydrase is a zinc metalloenzyme that catalyzes the hydration of carbon dioxide to bicarbonate. Replacing the active-site zinc with manganese yielded manganese-substituted carbonic anhydrase (CA[Mn]), which shows peroxidase activity with a bicarbonate-dependent mechanism. In the presence of bicarbonate and hydrogen peroxide, (CA[Mn]) catalyzed the efficient oxidation of o-dianisidine with kcat/KM=1.

Enhancing catalytic promiscuity for biocatalysis.

Catalytic promiscuity - the ability of a single active site to catalyse more than one chemical transformation - has a natural role in evolution and occasionally in biosynthesis of secondary metabolites. Catalytic promiscuity is more widespread than often recognized. Recent success in adding and enhancing such catalytic activities by protein engineering suggests new potential applications in enzyme-catalyzed organic synthesis.

Novel biocatalysis by database mining.

Broad-based adoption of biocatalytic methods will require widely available database tools, analogous to previous efforts compiling information for the facilitation of chemical synthesis. The analog to chemical reagents are enzymes. The analog to chemical synthetic routes are metabolic pathways.

Control of H+/lactose coupling by ionic interactions in the lactose permease of Escherichia coli.

A combinatorial approach was used to study putative interactions among six ionizable residues (Asp-240, Glu-269, Arg-302, Lys-319, His-322, and Glu-325) in the lactose permease. Neutral mutations were made involving five ion pairs that had not been previously studied. Double mutants, R302L/E325Q and D240N/H322Q, had moderate levels of downhill [(14)C]-lactose transport.

The murine IRAK2 gene encodes four alternatively spliced isoforms, two of which are inhibitory.

The interleukin-1 receptor-associated kinases (IRAKs) are important downstream signaling components of Toll-like receptors (TLRs). To date, four mammalian IRAKs have been found, namely IRAK-1, IRAK-2, IRAK-4, and IRAK-M. Herein, we show a detailed analysis of the genomic region encompassing the murine Irak2 gene and the molecular cloning of four isoforms of Irak2 (designated Irak2a, Irak2b, Irak2c, and Irak2d) generated by alternative splicing at the 5'-end of the gene.

Evidence for structural symmetry and functional asymmetry in the lactose permease of Escherichia coli.

Previous work on the lactose permease of Escherichia coli has shown that mutations along a face of predicted transmembrane segment 8 (TMS-8) play a critical role in conformational changes associated with lactose transport (Green, A. L., and Brooker, R.

Allelic Analysis of the Maize amylose-extender Locus Suggests That Independent Genes Encode Starch-Branching Enzymes IIa and IIb.

Starch branching enzymes (SBE) catalyze the formation of [alpha]-1,6-glucan linkages in the biosynthesis of starch. Three distinct SBE isoforms have been identified in maize (Zea mays L.) endosperm, SBEI, IIa, and IIb.