A new series of transition metal complexes of Co(III), Ni(II) and VO(IV) was synthesized with the bidentate Schiff base ligand (HL) derived from the condensation of 2-amino-3-benzyloxypyridine and 5-bromo salicylaldehyde.

Recombinant glycerol dehydratase ofKlebsiella pneumoniae was purified to homogeneity. The subunit composition of the enzyme was most probablya2b2c2 .When(R)- and (S)-propane-1,2-diolswere used independently as substrates, the rate with the (R)-enantiomer was 2.5 times faster than that with the (S)-isomer. In contrast to diol dehydratase,an iso-functional enzyme,the affinity of the enzyme for the (S)-isomer was essentially the same or only slightly higher than that for the (R)-isomer (Km(R) /Km(S) ¼1.5). ...

We report here the first crystal structure of a stable isosteric analogue of 1,3-bisphospho-D-glyceric acid (1,3-BPGA) bound to the catalytic domain of Trypanosoma cruzi glycosomal glyceraldehyde-3-phosphate dehydrogenase (gGAPDH)in which the two phosphoryl moieties interact with Arg249. This complex possibly illustrates a step of the catalytic process by which Arg249 may induce compression of the product formed, allowing its expulsion fromthe active site.

There are several different families of repeat proteins. In each, a distinct structural motif is repeated in tandem to generate an elongated structure. The nonglobular, extended structures that result are particularly well suited to present a large surface area and to function as interaction domains. Many repeat proteins have been demonstrated experimentally to fold and function as independent domains.

The crystal structure of pyruvate decarboxylase fromKluyveromyces lactis has been determined to 2.26 A˚ resolution. Like other yeast enzymes, Kluyveromyces lactispyruvate decarboxylase is subject to allosteric sub-strate activation. Binding of substrate at a regulatory site induces catalytic activity.

Phenylpyruvate decarboxylase (PPDC) ofAzospirillum brasilense, involved in the biosynthesis of the plant hormone indole-3-acetic acid and the anti-microbial compound phenylacetic acid, is a thiamine diphosphate-depend-ent enzyme that catalyses the nonoxidative decarboxylation of indole- and phenylpyruvate.

A complex of chagasin, a protein inhibitor fromTrypanosoma cruzi, and papain, a classic family C1 cysteine protease, has been crystallized. Kinetic studies revealed that inactivation of papain by chagasin is very fast (kon= 1.5·10 6 m )1 Æs )1 ), and results in the formation of a very tight, reversible complex (Ki =36pm), with similar or better rate and equilib-rium constants than those for cathepsins L and B.

c-Glutamyltranspeptidase (GGT; EC 2.3.2.2), an enzyme found in organ-isms from bacteria to mammals and plants, plays a central role in glutathi-one metabolism. Structural studies of GGTs from Escherichia coliand Helicobacter pylori have revealed detailed molecular mechanisms of catalysis and maturation.

The extracellular phytase of the plant-associatedKlebsiellasp. ASR1 is a member of the histidine-acid-phosphatase family and acts primarily as a scavenger of phosphate groups locked in the phytic acid molecule. The Klebsiellaenzyme is distinguished from theEscherichia coliphytase AppA by its sequence and phytate degradation pathway.

Laccases are copper-containing enzymes used in various applications, such as textile bleaching. Several crystal structures of laccases from fungi and bacteria are available, but ascomycete types of fungal laccases (asco-lac-cases) have been rather unexplored, and to date only the crystal structure ofMelanocarpus albomyceslaccase (MaL) has been published.

It has been reported that a human chloride intracellular channel (CLIC) protein, CLIC4, translocates to the nucleus in response to cellular stress, facilitated by a putative CLIC4 nuclear localization signal (NLS). The CLIC4 NLS adopts ana-helical structure in the native CLIC4 fold.

b-Linked glucans such as cellulose and xyloglucan are important compo-nents of the cell walls of most dicotyledonous plants. Theseb-linked glu-cans are constantly exposed to degradation by various endo-b-glucanases from pathogenic bacteria and fungi.

Onconase (ONC) is an amphibian member of the pancreatic ribonuclease superfamily that is selectively toxic to tumor cells. It is a much less efficient enzyme than the archetypal ribonuclease A and, in an attempt to gain fur-ther insight, we report the first atomic resolution crystal structure of ONC, determined in complex with sulfate ions at 100 K.

Taenia soliumis the cestode responsible for porcine and human cysticercosis. The ability of this parasite to establish itself in the host is related to its eva-sion of the immune response and its antioxidant defence system. The latter includes enzymes such as cytosolic Cu⁄Zn superoxide dismutase.

Ubiquitin carboxy-terminal hydrolase L5 (UCHL5) is a proteasome-associ-ated deubiquitinating enzyme, which, along with RPN11 and USP14, is known to carry out deubiquitination on proteasome. As a member of the ubiquitin carboxy-terminal hydrolase (UCH) family, UCHL5 is unusual because, unlike UCHL1 and UCHL3, it can process polyubiquitin chain.