Evolving Methanococcoides burtonii archaeal Rubisco for improved photosynthesis and plant growth.

In photosynthesis Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) catalyses the often rate limiting CO2-fixation step in the Calvin cycle. This makes Rubisco both the gatekeeper for carbon entry into the biosphere and a target for functional improvement to enhance photosynthesis and plant growth. Encumbering the catalytic performance of Rubisco is its highly conserved, complex catalytic chemistry.

Experienced and novice officers' generalized communication suspicion and veracity judgments.

Deception detection research has shown that police officers are less truth-biased and make their veracity judgments with greater confidence than do nonofficers. Here we examined nonofficers, novice officers, and experienced officers' response bias, confidence, and generalized communicative suspicion. In Experiment 1, novice officers aligned with nonofficers in terms of both generalized communicative suspicion scores and confidence, with both these groups scoring lower than experienced officers.

Two Essential Light Chains Regulate the MyoA Lever Arm To Promote Toxoplasma Gliding Motility.

Unlabelled: Key to the virulence of apicomplexan parasites is their ability to move through tissue and to invade and egress from host cells. Apicomplexan motility requires the activity of the glideosome, a multicomponent molecular motor composed of a type XIV myosin, MyoA. Here we identify a novel glideosome component, essential light chain 2 (ELC2), and functionally characterize the two essential light chains (ELC1 and ELC2) of MyoA in Toxoplasma.

Structural and mechanistic insight into alkane hydroxylation by Pseudomonas putida AlkB.

Pseudomonas putida GPo1 alkane hydroxylase (AlkB) is an integral membrane protein that catalyses the hydroxylation of medium-chain alkanes (C3-C12). 1-Octyne irreversibly inhibits this non-haem di-iron mono-oxygenase under turnover conditions, suggesting that it acts as a mechanism-based inactivator. Upon binding to the active site, 1-octyne is postulated to be oxidized to an oxirene that rapidly rearranges to a reactive ketene which covalently acylates nearby residues, resulting in enzyme inactivation.

Conformational analysis of isolated domains of Helicobacter pylori CagA.

The CagA protein of Helicobacter pylori is associated with increased virulence and gastric cancer risk. CagA is translocated into the host cell by a H. pylori type IV secretion system via mechanisms that are poorly understood.

Rubisco activity and regulation as targets for crop improvement.

Rubisco (ribulose-1,5-bisphosphate (RuBP) carboxylase/oxygenase) enables net carbon fixation through the carboxylation of RuBP. However, some characteristics of Rubisco make it surprisingly inefficient and compromise photosynthetic productivity. For example, Rubisco catalyses a wasteful reaction with oxygen that leads to the release of previously fixed CO(2) and NH(3) and the consumption of energy during photorespiration.

Characterization and two-dimensional crystallization of membrane component AlkB of the medium-chain alkane hydroxylase system from Pseudomonas putida GPo1.

The alkane hydroxylase system of Pseudomonas putida GPo1 allows it to use alkanes as the sole source of carbon and energy. Bacterial alkane hydroxylases have tremendous potential as biocatalysts for the stereo- and regioselective transformation of a wide range of chemically inert unreactive alkanes into valuable reactive chemical precursors. We have produced and characterized the first 2-dimensional crystals of the integral membrane component of the P.

Isoleucine 309 acts as a C4 catalytic switch that increases ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) carboxylation rate in Flaveria.

Improving global yields of important agricultural crops is a complex challenge. Enhancing yield and resource use by engineering improvements to photosynthetic carbon assimilation is one potential solution. During the last 40 million years C(4) photosynthesis has evolved multiple times, enabling plants to evade the catalytic inadequacies of the CO(2)-fixing enzyme, ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco).

An improved procedure for the purification of catalytically active alkane hydroxylase from Pseudomonas putida GPo1.

Bacterial alkane hydroxylases are of high interest for bioremediation applications as they allow some bacteria to grow in oil-contaminated environments. Furthermore, they have tremendous biotechnological potential as they catalyse the stereo- and regio-specific hydroxylation of chemically inert alkanes, which can then be used in the synthesis of pharmaceuticals and other high-cost chemicals. Despite their potential, progress on the detailed characterization of these systems has so far been slow mainly due to the lack of a robust procedure to purify its membrane protein component, monooxygenase AlkB, in a stable and active form.

Substrate-induced assembly of Methanococcoides burtonii D-ribulose-1,5-bisphosphate carboxylase/oxygenase dimers into decamers.

Like many enzymes, the biogenesis of the multi-subunit CO(2)-fixing enzyme ribulose-1,5-bisphosphate (RuBP) carboxylase/oxygenase (Rubisco) in different organisms requires molecular chaperones. When expressed in Escherichia coli, the large (L) subunits of the Rubisco from the archaeabacterium Methanococcoides burtonii assemble into functional dimers (L(2)). However, further assembly into pentamers of L(2) (L(10)) occurs when expressed in tobacco chloroplasts or E.

Methyltetrahydrofolate:corrinoid/iron-sulfur protein methyltransferase (MeTr): protonation state of the ligand and active-site residues.

Methyltetrahydrofolate:corrinoid/iron-sulfur protein methyltransferase (MeTr) catalyzes the transfer of the N5-methyl group from N5-methyltetrahydrofolate (CH(3)THF) to the cobalt center of a corrinoid/iron-sulfur protein, a reaction similar to that of cobalamin-dependent methionine synthase (MetH). For such a reaction to occur, CH(3)THF is expected to be activated by a stereospecific protonation at the N5 position. It has been shown experimentally that binding to MeTr is associated with a pK(a) increase and proton uptake.

Combining docking and molecular dynamic simulations in drug design.

A rational approach is needed to maximize the chances of finding new drugs, and to exploit the opportunities of potential new drug targets emerging from genomic and proteomic initiatives, and from the large libraries of small compounds now readily available through combinatorial chemistry. Despite a shaky early history, computer-aided drug design techniques can now be effective in reducing costs and speeding up drug discovery. This happy outcome results from development of more accurate and reliable algorithms, use of more thoughtfully planned strategies to apply them, and greatly increased computer power to allow studies with the necessary reliability to be performed.

Integron-sequestered dihydrofolate reductase: a recently redeployed enzyme.

The introduction and wide use of antibacterial drugs has resulted in the emergence of resistant organisms. DfrB dihydrofolate reductase (DHFR) is a bacterial enzyme that is uniquely associated with mobile gene cassettes within integrons, and confers resistance to the drug trimethoprim. This enzyme has intrigued microbiologists since it was discovered more than thirty years ago because of its simple structure, enzymatic inefficiency and its virtual insensitivity to trimethoprim.

Multiple ligand-binding modes in bacterial R67 dihydrofolate reductase.

R67 dihydrofolate reductase (DHFR), a bacterial plasmid-encoded enzyme associated with resistance to the drug trimethoprim, shows neither sequence nor structural homology with the chromosomal DHFR. It presents a highly symmetrical toroidal structure, where four identical monomers contribute to the unique central active-site pore. Two reactants (dihydrofolate, DHF), two cofactors (NADPH) or one of each (R67*DHF*NADPH) can be found simultaneously within the active site, the last one being the reactive ternary complex.