Biomedical subjects

Lawrence J DeLucas

Publications and source records attributed to Lawrence J DeLucas.

5 recordsLinked to original sources

PubMed2003

Tethered dimers as NAD synthetase inhibitors with antibacterial activity.

The solution-phase parallel synthesis of tethered dimers was employed to identify lead inhibitors of bacterial NAD synthetase. Active dimers contained two aromatic end groups joined by a polymethylene linker, with one end group containing a permanent positive charge. Effective inhibitors of NAD synthetase also inhibited the growth of Gram-positive (but not Gram-negative) bacteria, including antibiotic-resistant strains. The desmethyl precursors of active inhibitors lacked a permanent positive charge and were inactive as either enzyme inhibitors or antibacterial agents. Similarly, a close structural analogue of the most active inhibitors contained two additional ether oxygens in the tether and was inactive in both assays. These results are consistent with the premise that NAD synthetase inhibition is responsible for the antibacterial actions and support further studies on NAD synthetase as a new target for antibacterial agents.

Amide Synthases↗

PubMed2003

Purification, nanocrystallization and preliminary X-ray analysis of a C-terminal part of tropomodulin protein 1, isoform A, from Caenorhabditis elegans.

The C-terminal part of tropomodulin protein 1, isoform A, from Caenorhabditis elegans was expressed in Escherichia coli and purified to homogeneity. Optimized from the initial nanoscreen, crystals grew to dimensions of 0.25 x 0.15 x 0.15 mm at 277 K using 28.0%(v/v) PEG 400 as the precipitant by the hanging-drop vapor-diffusion technique. A data set of 94.9% completeness was collected to a resolution of 1.98 A at 100 K using a synchrotron X-ray source (SER-CAT). The crystals belong to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 31.7, b = 50.6, c = 107.1 A, and contained one molecule per asymmetric unit.

Amino Acid Sequence↗

PubMed2003

Efficient protein crystallization.

High-throughput molecular biology and crystallography advances have placed an increasing demand on crystallization, the one remaining bottleneck in macromolecular crystallography. This paper describes three experimental approaches, an incomplete factorial crystallization screen, a high-throughput nanoliter crystallization system, and the use of a neural net to predict crystallization conditions via a small sample (approximately 0.1%) of screening results. The use of these technologies has the potential to reduce time and sample requirements. Initial experimental results indicate that the incomplete factorial design detects initial crystallization conditions not previously discovered using commercial screens. This may be due to the ability of the incomplete factorial screen to sample a broader portion of "crystallization space," using a multidimensional set of components, concentrations, and physical conditions. The incomplete factorial screen is complemented by a neural network program used to model crystallization. This capability is used to help predict new crystallization conditions. An automated, nanoliter crystallization system, with a throughput of up to 400 conditions/h in 40-nl droplets (total volume), accommodates microbatch or traditional "sitting-drop" vapor diffusion experiments. The goal of this research is to develop a fully-automated high-throughput crystallization system that integrates incomplete factorial screen and neural net capabilities.

Computer Simulation↗

PubMed2003

The Southeast Collaboratory for Structural Genomics: a high-throughput gene to structure factory.

The Southeast Collaboratory for Structural Genomics consists of four working groups. The protein production group supplies/develops high-output production of Pyrococcus furiosus, Caenorhabditis elegans, and selected human proteins. The X-ray crystallography group conducts high-throughput structure production in parallel with production-related research/development in nanocrystallization robotics, capillary crystallization cassette, synchrotron/home X-ray instrumentation, sample mounting robotics, data processing and pipelined structure analysis, combined refinement/validation protocols, and direct use of unlabeled native crystals (Direct Crystallography). The NMR group emphasizes/develops sample screening and backbone structure determination from residual dipolar coupling data. The bioinformatics group implements/develops local database interfaces, pipelined sequence/structure information search/updates, and database/bioinformatics toolkits.

Animals↗

PubMed2002

Crystal structure of the cytoskeleton-associated protein glycine-rich (CAP-Gly) domain.

Cytoskeleton-associated proteins (CAPs) are involved in the organization of microtubules and transportation of vesicles and organelles along the cytoskeletal network. A conserved motif, CAP-Gly, has been identified in a number of CAPs, including CLIP-170 and dynactins. The crystal structure of the CAP-Gly domain of Caenorhabditis elegans F53F4.3 protein, solved by single wavelength sulfur-anomalous phasing, revealed a novel protein fold containing three beta-sheets. The most conserved sequence, GKNDG, is located in two consecutive sharp turns on the surface, forming the entrance to a groove. Residues in the groove are highly conserved as measured from the information content of the aligned sequences. The C-terminal tail of another molecule in the crystal is bound in this groove.

Amino Acid Sequence↗