Genes encoding 2-deoxy-d-ribose-5-phosphate aldolase (DERA) homologues from two hyperthermophiles, the archaeon Pyrobaculum aerophilum and bacterium Thermotoga maritima, were expressed individually in Escherichia coli, after which structures activities of enzymes produced characterized compared with those E. coli DERA. To our surprise, hyperthermophilic DERAs showed much greater catalysis sequential aldol condensation using three acetaldehydes as substrates than enzyme, even at a low...

A stable NADP+-dependent d-amino acid dehydrogenase (DAADH) was recently created from Ureibacillus thermosphaericusmeso-diaminopimelate through site-directed mutagenesis. To produce a novel DAADH mutant with different substrate specificity, the crystal structure of apo-DAADH determined at resolution 1.78 Å, and amino residues responsible for specificity were evaluated using additional By introducing single D94A mutation, enzyme's dramatically altered; utilized d-phenylalanine as most...

The crystal structure of a L-threonine dehydrogenase (L-ThrDH; EC 1.1.1.103) from the psychrophilic bacterium Flavobacterium frigidimaris KUC-1, which shows no sequence similarity to conventional L-ThrDHs, was determined in presence NAD and substrate analog, glycerol. asymmetric unit consisted two subunits related by two-fold rotation axis. Each monomer Rossmann-fold domain carboxyl-terminal catalytic domain. overall fold F. L-ThrDH showed significant that UDP-galactose 4-epimerase (GalE);...

The crystal structure of an extremely thermostable multicopper oxidase (McoP) from the hyperthermophilic archaeon Pyrobaculum aerophilum was determined at a resolution 2.0 Å. overall fold comprised three cupredoxin-like domains and main-chain coordinates enzyme were similar to those oxidases Escherichia coli (CueO) Bacillus subtilis (CotA). However, there clear topological differences around domain 3 between McoP other two enzymes: methionine-rich helix in CueO protruding CotA not present...

Abstract NAD(P)-dependent dehydrogenases differ according to their coenzyme preference: some prefer NAD, others NADP and still exhibit dual cofactor specificity. The structure of a newly identified archaeal homoserine dehydrogenase showed this enzyme have strong preference for NADP. However, did not act as with enzyme, but inhibitor NAD-dependent oxidation. Structural analysis site-directed mutagenesis that the large number interactions between are responsible lack reactivity towards This...

The crystal structure of the highly thermostable L-aspartate dehydrogenase (L-aspDH; EC 1.4.1.21) from hyperthermophilic archaeon Archaeoglobus fulgidus was determined in presence NAD and a substrate analog, citrate. dimeric A. L-aspDH refined at resolution 1.9 A with crystallographic R-factor 21.7% (R(free) = 22.6%). indicates that each subunit consists two domains separated by deep cleft containing an active site. Structural comparison L-aspDH/NAD/citrate ternary complex Thermotoga...

Crystal structures of Lactobacillus buchneri isoleucine 2-epimerase, a novel branched-chain amino-acid racemase, were determined for the enzyme in apo form, complex with pyridoxal 5'-phosphate (PLP), N-(5'-phosphopyridoxyl)-L-isoleucine (PLP-L-Ile) and N-(5'-phosphopyridoxyl)-D-allo-isoleucine (PLP-D-allo-Ile) at resolutions 2.77, 1.94, 2.65 2.12 Å, respectively. The assembled as tetramer, each subunit being composed N-terminal, C-terminal large PLP-binding domains. active-site cavity...

To evaluate the structure-function relationships of invertebrate lysozymes, a new invertebrate-type (i-type) lysozyme was isolated from common orient clam (Meretrix lusoria) and tertiary structure this enzyme determined. Comparison with those chicken Venerupi philippinarum lysozymes revealed that location side chain second catalytic residue, an aspartic acid, N-acetylglucosamine trimer bound at subsites A-C were different. Furthermore, amino acid electrostatically interacting Asp30 in V....

To determine the structure and functional relationships of invertebrate lysozymes, we isolated a new (i)-type lysozyme from common orient clam (Meretrix lusoria) determined complete amino acid sequence two isozymes that differed by one acid. The showed 65% similarity to Venerupis philippinarum (Tapes japonica), it was therefore classified as an i-type lysozyme. lytic activities this were similar those previously reported bivalve but unlike V. lysozyme, did not exhibit increase in activity...

The crystal structure of a D-tagatose 3-epimerase-related protein (TM0416p) encoded by the hypothetical open reading frame TM0416 in genome hyperthermophilic bacterium Thermotoga maritima was determined at resolution 2.2 A. asymmetric unit contained two homologous subunits and dimer generated twofold symmetry. main-chain coordinates enzyme monomer proved to be similar those 3-epimerase from Pseudomonas cichorii D-psicose Agrobacterium tumefaciens; however, TM0416p exhibited unique...

A gene encoding an L-lysine dehydrogenase was identified in the hyperthermophilic archaeon Pyrococcus horikoshii. The overexpressed Escherichia coli, and its product purified characterized. expressed enzyme is most thermostable yet described, with a half-life of 180 min at 100 degrees C. enzyme's catalytic activity Delta(1)-piperideine-6-carboxylate, which makes this 6-dehydrogenase (EC 1.4.1.18) that catalyzes reductive deamination epsilon- amino group type NAD-dependent amine...

To characterize the hydrogen-bonding network in lysozyme, we focused on residue of Asp48 located at active site hen egg-white lysozyme. We constructed a mutant lysozyme (D48A) and analyzed using (GlcNAc)3 chitin-affinity chromatography. The substrate binding subsites D-F D48A activity against (GlcNAc)5 were decreased. parameters rate constants obtained from computer simulations confirmed these changes. In crystal structure, (GlcNAc)4 was same position as wildtype. However, side chains Arg45...

Methylmalonyl-CoA mutase (MCM) requires 5'-deoxyadenosylcobalamin (AdoCbl) as a cofactor and is widely distributed in organisms from bacteria animals. Although genes encoding putative MCMs are present many archaea, they separately encoded large small subunits. The subunits of archaeal MCM similar to the catalytic AdoCbl-binding domains human MCM, respectively. In Pyrococcus horikoshii OT3, PH1306 PH0275 encode subunits, Because information on extremely restricted, we examined functional...