The field of antibiotic drug discovery and the monitoring of new antibiotic resistance elements have yet to fully exploit the power of the genome revolution. Despite the fact that the first genomes sequenced of free living organisms were those of bacteria, there have been few specialized bioinformatic tools developed to mine the growing amount of genomic data associated with pathogens. In particular, there are few tools to study the genetics and genomics of antibiotic resistance and how it impacts bacterial populations, ecology, and the clinic. We have initiated development of such tools in the form of the Comprehensive Antibiotic Research Database (CARD; http://arpcard.mcmaster.ca). The CARD integrates disparate molecular and sequence data, provides a unique organizing principle in the form of the Antibiotic Resistance Ontology (ARO), and can quickly identify putative antibiotic resistance genes in new unannotated genome sequences. This unique platform provides an informatic tool that bridges antibiotic resistance concerns in health care, agriculture, and the environment.A ntibiotic resistance is an increasing crisis as both the range of microbial antibiotic resistance in clinical settings expands and the pipeline for development of new antibiotics contracts (1). This problem is compounded by the global genomic scope of the antibiotic resistome, such that antibiotic resistance spans a continuum from genes in pathogens found in the clinic to those of benign environmental microbes along with their proto-resistance gene progenitors (2, 3). The recent emergence of New Delhi metallo-ß-lactamase (NDM-1) in Gram-negative organisms (4), which can hydrolyze all ␤-lactams with the exception of monobactams, illustrates the capacity of new antibiotic resistance genes to emerge rapidly from as-yet-undetermined reservoirs. Surveys of genes originating from both clinical and environmental sources (microbes and metagenomes) will provide increasing insight into these reservoirs and offer predictive capacity for the emergence and epidemiology of antibiotic resistance.The increasing opportunity to prepare a broader and comprehensive antibiotic resistance gene census is facilitated by the power and falling costs of next-generation DNA sequencing. For example, whole-genome sequencing (WGS) is being increasingly used to examine new antibiotic-resistant isolates discovered in clinical settings (5). Additionally, culture-independent metagenomic surveys are adding tremendously to the pool of known genes and their distribution outside clinical settings (6, 7). These approaches have the advantage of providing a rapid survey of the antibiotic resistome of new strains, the discovery of newly emergent antibiotic resistance genes, the epidemiology of antibiotic resistance genes, and the horizontal gene transfer (HGT) of known antibiotic resistance genes through plasmids and transposable elements. However, despite the existence of tools for general annotation of prokaryotic genomes (see, e.g., reference 8), prediction of an antibiotic resista...

Corynebacterium glutamicum contains four serine/threonine protein kinases (STPKs) named PknA, PknB, PknG, and PknL. Here we present the first biochemical and comparative analysis of all four C. glutamicum STPKs and investigate their potential role in cell shape control and peptidoglycan synthesis during cell division. In vitro assays demonstrated that, except for PknG, all STPKs exhibited autokinase activity. We provide evidence that activation of PknG is part of a phosphorylation cascade mechanism that relies on PknA activity. Following phosphorylation by PknA, PknG could transphosphorylate its specific substrate OdhI in vitro. A mass spectrometry profiling approach was also used to identify the phosphoresidues in all four STPKs. The results indicate that the nature, number, and localization of the phosphoacceptors varies from one kinase to the other. Disruption of either pknL or pknG in C. glutamicum resulted in viable mutants presenting a typical cell morphology and growth rate. In contrast, we failed to obtain null mutants of pknA or pknB, supporting the notion that these genes are essential. Conditional mutants of pknA or pknB were therefore created, leading to partial depletion of PknA or PknB. This resulted in elongated cells, indicative of a cell division defect. Moreover, overexpression of PknA or PknB in C. glutamicum resulted in a lack of apical growth and therefore a coccoid-like morphology. These findings indicate that pknA and pknB are key players in signal transduction pathways for the regulation of the cell shape and both are essential for sustaining corynebacterial growth.Corynebacterium glutamicum is a leading industrial amino acid producer and a model organism of the Corynebacteriaceae, a suborder of the actinomycetes that also includes the genus Mycobacterium. This soil-borne, nonpathogenic Grampositive actinomycete, which is widely used in the industrial production of amino acids, such as L-lysine and L-glutamic acid (1), has been extensively studied leading to the development of efficient genetic manipulation systems (3).The genetics of cell growth and cell division of C. glutamicum started even before the complete genome sequence was available. The earliest studies focused on the sequencing and characterization of corynebacterial genes present in the conserved division and cell wall cluster (2). Once the genome sequence was available, it was evident that this bacterium, as well as different members of the actinomycetes, was deficient in many essential genes for cell division (3) and therefore corresponded to a minimalist version of a more sophisticated cell division apparatus (divisome) present in other bacteria. For instance, C. glutamicum is lacking genes homologue to ftsA (an actin homologue), to positive regulators involved in FtsZ polymerization such as zipA or zapA, or to negative regulators such as ezrA, noc, slmA, sulA, and minCD (3). Moreover, several essential cell division genes (i.e. ftsN and ftsL) are absent in C. glutamicum. Unlike other bacterial models, peptidoglycan (PG) ...

The OdhI protein is key regulator of the TCA cycle in Corynebacterium glutamicum. This highly conserved protein is found in GC rich Gram-positive bacteria (e.g., the pathogenic Mycobacterium tuberculosis). The unphosphorylated form of OdhI inhibits the OdhA protein, a key enzyme of the TCA cycle, whereas the phosphorylated form is inactive. OdhI is predicted to be mainly a single FHA domain, a module that mediates protein-protein interaction through binding of phosphothreonine peptides, with a disordered N-terminal extension substrate of the serine/threonine protein kinases. In this study, we solved the solution structure of the unphosphorylated and phosphorylated isoforms of the protein. We observed a major conformational change between the two forms characterized by the binding of the phosphorylated N-terminal part of the protein to its own FHA domain, consequently inhibiting it. This structural observation corresponds to a new autoinhibition mechanism described for a FHA domain protein.