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The NorthEastern Collaborative Access Team (NE-CAT) focuses on the design and operation of synchrotron X-ray beamlines for the solution of technically challenging structural biology problems and provides an important resource for the national and international research community. Currently NE-CAT operates two undulator beamlines: 24ID-C - tunable in the energy range from 6 to 22keV and 24ID-E - not-tunable, but optimized for Se SAD experiments. Both beamlines are equipped with state-of-the-art instrumentation. MD2 microdiffractometers installed at both beamlines provide very clean beams down to 5 microns in diameter and are capable of visualizing micron-sized crystals. Large area detectors (ADSC Quantum 315 at 24ID-E beamline and Pilatus-6MF at 24ID-C beamline), not only provide the best diffraction data, but also make possible to resolve large unit cells. Both beamlines are equipped with ALS style automatic sample mounters. Locally developed software suite RAPD provides data collection strategies, quasi-real time data integration and scaling and simple automated MR/SAD pipeline through 384 core computing cluster. Users of the beamlines are supported by experienced resident crystallographers. To meet the needs of technically challenging crystallographic projects, cutting-edge hardware and software ideas are implemented. A summary of beamline capabilities, technology, scientific highlights and details of availability will be presented. Funding for NE-CAT is provided through P41 grant from the NIGMS and from the NE-CAT member institutions.
abstracts
Vitamin B12 (Cobalamin;Cbl;B12; Figure) is a water soluble vitamin and is an essential component for the growth and development of many eukaryotes and prokaryotes organisms. B12 coordinates a cobalt ion in the center of the ring through the four pyrrole nitrogen atoms, the fifth ligand is dimethylbenzimidazole (DMB) moiety and the sixth ligand can be methyl group, deoxyadenosyl, cyanide or OH-. The structurally diverse groups of B12 binding proteins involved in various important biological functions. B12 adopts either base-on or base-off conformation in B12 binding proteins (Figure). An in-depth analysis on these structures was carried out using PDB coordinates (www.pdb.org) of a carefully chosen database of B12 binding proteins to correlate the overall folding of the molecule with phylogeny, the B12 interactions, and with biological function. The chosen database can be divided into three distinct groups. The first group is B12 transport proteins in mammals and the second is B12 transport proteins in E.Coli. The third group can be broadly clarified as B12-dependent enzymes. Results: The molecular architecture of the B12 binding proteins is diverse. It varies from a two-domain to multi-domain proteins. An analysis on the environment around B12 molecule shows that hydrogen bonds or vander waals interactions are dominant interactions between B12 and protein. Both conventional hydrogen bonds (N-H....X and O-H....X) and weak C-H....X hydrogen bonds play important role in these interactions. The number of protein residues interacting with B12 varies widely from 2 to 18 residues, depending on the nature of biological function. The analysis clearly establishes that B12 is amazingly adoptive to wide range of environments, namely polar, non-polar or charged. The B12 uses its functional groups both at head, corrin ring and in tail region (phosphate or DMB groups) at optimum level to form stable complex with partner proteins. Details will be presented.
