The crystal structure of the highly thermostablel-aspartate dehydrogenase
(l-aspDH; EC 126.96.36.199) from the hyperthermophilic archaeon Archaeoglo-bus fulgiduswas determined in the presence of NAD and a substrate ana-log, citrate. The dimeric structure of A. fulgidusl-aspDH was refined at
a resolution of 1.9 A
with a crystallographicR-factor of 21.7% (Rfree ¼
Antibodies and their fragments are attractive binding proteins because their
high binding strength is generated by several hypervariable loop regions,
and because high-quality libraries can be prepared from the vast gene clus-ters expressed by mammalian lymphocytes. Recent explorations of new
genome sequences and protein structures have revealed various small,
nonantibody scaffold proteins.
During pathogenesis of transmissible spongiform encephalopathies (TSEs)
an abnormal form (PrP
) of the host encoded prion protein (PrP
) accu-mulates in insoluble fibrils and plaques. The two forms of PrP appear to
have identical covalent structures, but differ in secondary and tertiary
Most of the biochemical and biophysical processes of proteins take place
at membranes, and are thus under the influence of strong local electric
fields, which are likely to affect the structure as well as the reaction mecha-nism and dynamics.
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.
We solved the 1.8 A˚
crystal structure ofb-fructofuranosidase from Bifido-bacterium longumKN29.1 – a unique enzyme that allows these probiotic
bacteria to function in the human digestive system. The sequence ofb-fruc-tofuranosidase classifies it as belonging to the glycoside hydrolase family
Fusidic acid (FA) is a bacteriostatic antibiotic that locks elongation factor G
(EF-G) on the ribosome in a post-translocational state. It is used clinically
against Gram-positive bacteria such as pathogenic strains of Staphylo-coccus aureus, but no structural information has been available for EF-G
from these species.
Two structures of monomeric methionyl-tRNA synthetase, fromMycobac-terium smegmatis, in complex with the ligands methionine⁄adenosine and
methionine, were analyzed by X-ray crystallography at 2.3 A˚ and at 2.8 A˚
respectively. The structures demonstrated the flexibility of the multidomain
enzyme. A new conformation of the structure was identified in which the
connective peptide domain bound more closely to the catalytic domain
than described previously.
The crystal structures ofThermoactinomyces vulgariscyclo⁄maltodextrin-binding protein (TvuCMBP) complexed with a-cyclodextrin (a-CD),
b-cyclodextrin (b-CD) and maltotetraose (G4) have been determined. A
common functional conformational change among all solute-binding pro-teins involves switching from an open form to a closed form, which facili-tates transporter binding.
Metallothioneins (MTs) are cysteine-rich, metal-binding proteins known to
provide protection against cadmium toxicity in mammals. Metal exchange
ions for Cd
ions in metallothioneins is a critical process for
which no mechanistic or structural information is currently available.
The crystal structure of glycerol kinase from the hyperthermophilic archa-eon Thermococcus kodakaraensis(Tk-GK) in a dimeric form was deter-mined at a resolution of 2.4 A˚ . This is the first crystal structure of a
hyperthermophilic glycerol kinase.
The three-dimensional structures of some components of snake venoms
forming so-called ‘three-fingered protein’ domains (TFPDs) are similar to
those of the ectodomains of activin, bone morphogenetic protein and trans-forming growth factor-breceptors, and to a variety of proteins encoded by
Palytoxin is a marine toxin responsible for a fatal type of poisoning in
humans named clupeotoxism, with symptoms such as neurologic distur-bances. It is believed that it binds to the Na
-ATPase from the extra-cellular side and modifies cytosolic ions; nevertheless, its effects on internal
cell structures, such as the cytoskeleton, which might be affected by these
initial events, have not been fully elucidated.
The structure of human telomeric DNA is controversial; it depends upon
the sequence contexts and the methodologies used to determine it. The
solution structure in the presence of K
is particularly interesting, but the
structure is yet to be elucidated, due to possible conformational heterogen-eity.
We describe the cloning, overexpression, purification, characterization and
crystal structure of chitinase G, a single-domain family 19 chitinase from
the Gram-positive bacterium Streptomyces coelicolorA3(2). Although chi-tinase G was not capable of releasing 4-methylumbelliferyl from artificial
chitooligosaccharide substrates, it was capable of degrading longer chito-oligosaccharides at rates similar to those observed for other chitinases.
Human serum albumin (HSA) exists in both reduced and oxidized forms,
and the percentage of oxidized albumin increases in several diseases. How-ever, little is known regarding the pathophysiological significance of oxida-tion due to poor characterization of the precise structural and functional
properties of oxidized HSA.
We have investigated the molecular mechanisms that
produce different structural and functional behavior in the
monomeric and trimeric forms of seminal vesicle protein
no. 4, a protein with immunomodulatory, anti-inflamma-tory, and procoagulant activity secreted from the rat
seminal vesicle epithelium. The monomeric and trimeric
forms were characterized in solution by CD.
Acyl-CoA dehydrogenases and acyl-CoA oxidases are two
closely related FAD-containing enzyme families that are
present inmitochondriaandperoxisomes, respectively. They
catalyze the dehydrogenation of acyl-CoA thioesters to the
correspondingtrans-2-enoyl-CoA. This review examines the
structure of medium chain acyl-CoA dehydrogenase, as
a representative of the dehydrogenase family, with respect
to the catalytic mechanism and its broad chain length
The crystal structures of the wild-type HIV-1 protease (PR)
and the two resistant variants, PRV82Aand PRL90M,have
been determined in complex with the antiviral drug, indi-navir, to gain insight into the molecular basis of drug
resistance. V82A and L90M correspond to an active site
mutation and nonactive site mutation, respectively. The
inhibition (Ki)of PRV82Aand PRL90Mwas 3.3- and 0.16-fold, respectively, relative to the value for PR. They showed
only a modest decrease, of 10–15%, in theirkcat
relative to PR. ...
The divalent metal transporter (DMT1) is a 12-transmem-brane domain protein responsible for dietary iron uptake in
the duodenum and iron acquisition from transferrin in
peripheral tissues. The transmembrane domain 4 (TM4)
of DMT1 has been shown to be crucial for its biological
function. Here we report the 3D structure and topology of
the DMT1-TM4 peptide by NMR spectroscopy with
simulated annealing calculations in membrane-mimetic
environments, e.g. 2,2,2-trifluoroethanol and SDS micelles.