STRUCTURE FUNCTION DIVERSITY WITHIN THE PHOSPHOENOLPYRUVATE MUTASE / ISOCITRATE LYASE SUPERFAMILY AS REVEALED BY THE ENZYMES OXALOACETATE DECARBOXYLASE AND 2,3-DIMETHYLMALATE LYASE

Two members of the phosphoenolpyruvate mutase (PEPM) / isocitrate lyase (ICL) superfamily were investigated to study their structure-function relationships and to identify sequence signatures that define a particular function. The first enzyme (PA4872) was a protein of unknown function from Pseudomonas aeruginosa. The second enzyme from Aspergillus niger (An07g08390) was thought to be an oxaloacetate acetyl hydrolase (OAH) because of its high sequence identity (~60%) to an enzyme with confirmed OAH activity. The X-ray crystal structure determination of PA4872 revealed unique features that guided the design of biochemical experiments, which ultimately led to the discovery that the enzyme is an oxaloacetate decarboxylase (OAD). Two structures of An07g08390, one with bound Mg2+ and the second with bound Mn2+ and the inhibitor 3,3-difluorooxaloacetate, were determined. The functional studies demonstrated that although the enzyme has OAH activity, it has a far better activity as a 2R,3S-dimethylmalate lyase (DMML). The active site structure of DMML indicated a proline residue (Pro240) as a marker of DMML function along with confirming the conserved locations of previously established signature residues for lyase activity. OAD is the founding member of a family within the PEPM / ICL superfamily and thus defines the function of the remaining family members. However, the biological context in which OAD functions remains unknown. DMML is known to function in the nicotinate catabolism pathway but not all the members of the pathway are present in A. niger. Transcriptome analysis suggests that the DMML encoding gene is under carbon catabolite repression but the pathway in which the enzyme functions has not yet been identified

Trendspotting in the Protein Data Bank

The Protein Data Bank (PDB) was established in 1971 as a repository for the three dimensional structures of biological macromolecules. Since then, more than 85000 biological macromolecule structures have been determined and made available in the PDB archive. Through analysis of the corpus of data, it is possible to identify trends that can be used to inform us abou the future of structural biology and to plan the best ways to improve the management of the ever-growing amount of PDB data

Trendspotting in the Protein Data Bank

The Protein Data Bank (PDB) was established in 1971 as a repository for the three dimensional structures of biological macromolecules. Since then, more than 85000 biological macromolecule structures have been determined and made available in the PDB archive. Through analysis of the corpus of data, it is possible to identify trends that can be used to inform us abou the future of structural biology and to plan the best ways to improve the management of the ever-growing amount of PDB data

Enhancing UCSF Chimera through web services

Integrating access to web services with desktop ap-plications allows for an expanded set of application features, including performing computationally in-tensive tasks and convenient searches of databases. We describe how we have enhanced UCSF Chimer

The eyes have it: using X-ray crystallography to determine the binding modes of medically relevant ruthenium/DNA complexes

Ruthenium polypyridyl complexes have been intensively studied in many laboratories around the world for their potential applications in chemotherapy, including photodynamic therapy, and as useful DNA probes and sensors in cells. This chapter discusses the ways in which X-ray crystallography can contribute to our understanding of these applications at the molecular level. The design of useful compounds relies on assumptions about the shape and possible flexibility of the molecular target, and an appreciation of how and why a small change in the molecular design can have a major impact on the effectiveness of the compound