Biomedical subjects

M Harkiolaki

Publications and source records attributed to M Harkiolaki.

3 recordsLinked to original sources

PubMed2001

ARP/wARP and molecular replacement.

The aim of ARP/wARP is improved automation of model building and refinement in macromolecular crystallography. Once a molecular-replacement solution has been obtained, it is often tedious to refine and rebuild the initial (search) model. ARP/wARP offers three options to automate that task to varying extents: (i) autobuilding of a completely new model based on phases calculated from the molecular-replacement solution, (ii) updating of the initial model by atom addition and deletion to obtain an improved map and (iii) docking of a structure onto a new (or mutated) sequence, followed by rebuilding and refining the side chains in real space. A few examples are presented where ARP/wARP made a considerable difference in the speed of structure solution and/or made possible refinement of otherwise difficult or uninterpretable maps. The resolution range allowing complete autobuilding of protein structures is currently 2.0 A, but for map improvement considerable advances over more conventional refinement techniques are evident even at 3.2 A spacing.

Alu Elements↗

PubMed2001

New crystal forms of Trypanosoma cruzi dUTPase.

The dUTPase from Trypanosoma cruzi has been crystallized in two crystal forms, both belonging to space group P6(3)22, with unit-cell parameters a = b = 134.67, c = 148.66 A (form I, two molecules per asymmetric unit) and a = b = 136.43, c = 68.71 A (form II, one molecule per asymmetric unit). Single-wavelength data have been collected using synchrotron radiation to 3.0 A for crystal form I and to 2.4 A for crystal form II and structure solution is under way. T. cruzi dUTPase is a potential target for anti-protozoan drug design.

Animals↗

PubMed2001

Crystallization and preliminary crystallographic analysis of deoxyuridine 5'-triphosphate nucleotidohydrolase from Bacillus subtilis.

Single crystals of purified homotrimeric deoxyuridine 5'-triphosphate nucleotidohydrolase (dUTPase) from Bacillus subtilis have been grown under several different conditions using vapour diffusion. X-ray diffraction data have been collected using synchrotron radiation from three crystal forms of the unliganded enzyme and from enzyme cocrystallized with a substrate analogue and inhibitor, dUDP, and a metal ion, Sr(2+). The three crystal forms of unliganded enzyme belong to hexagonal (P6(3)), orthorhombic (P2(1)2(1)2) and cubic (P2(1)3) space groups and data have been recorded to 1.75, 1.90 and 2.50 A spacing, respectively. Crystals grown in the presence of dUDP and Sr(2+) belong to the orthorhombic space group P2(1)2(1)2(1) and data were measured to 1.90 A spacing. Solution of the hexagonal crystal form by molecular replacement using the dUTPase from feline immunodeficiency virus as a search model is in progress.

Bacillus subtilis↗