Protein and Peptide Letters - Volume 17, Issue 2, 2010

36 mutants of the Sulfolobus solfataricus amidase were analyzed by comparing biochemical data to structural data obtained by a learning machine. The analysis shows that beside well known catalytic residues, amino acid residues Arg197, Lys209 and Asp228 are important for the catalytic activity of the signature thermophilic amidase.

The peptidyl prolyl isomerase (Pin1) that catalyzes the isomerization of peptide bonds involving proline and phosphorylated serine/threonine/tyrosine and alters the conformation and differential folding has been implicated in the regulation and function of phosphorylated proteins including mitotic and cell cycle proteins viz. Cdc25c, Bcl2, p53 etc. DNA topoisomerase IIα is one of the nuclear enzymes that m Read More

Two cell-penetrating peptides, a Pro-rich peptide derivative, acetyl-(Val-Arg-Leu-Pro-Pro-Pro)3-Gly-Cys amide, and an octaarginine derivative, acetyl-Arg-Arg-Arg-Arg-Arg-Arg-Arg-Arg-Gly-Cys amide, were prepared by the solid phase method. Each peptide was coupled to the heterobifunctional cross-linking reagent, 6-maleimidohexanoic acid N-hydroxysuccinimide ester, and then conjugated to the Adenovirus Read More

Tert- butylation of tryptophan (2', 5', 7'- tri tertiary butyl tryptophan), formed during acidolytic cleavage of synthetic peptides Ac-KLVYWAE-CONH2 (A-YW) and Ac-KLVWWAE-CONH2 (A-WW), that are analogs of the fragment of Alzheimer's β-amyloid peptide Ac-KLVFFAE-CONH2, during solid-phase peptide synthesis, was characterized by matrix- assisted laser desorption/ionization time of flight/time of flight (MALDI TOF/TOF) Read More

Tapes japonica lysozyme (TJL), which belongs to the invertebrate-type lysozyme family, has a unique dimer formation. The residues, which include catalytic residues (glutamate 18 and aspartate 30), at the dimer interface form electrostatic interactions. Our previous study suggested that increasing the NaCl concentration switched TJL from a dimer to monomer structure, which increased TJL activity. Therefore, conversion Read More

Amyloid fibril formation of amyloid beta peptide 1-40 (Aβ 1-40) was reported to be retarded in the presence of 150mM phosphate buffer at pH 7 [Monji, Ustumi, Ueda, Imoto, Yoshida, Hashioka, Tashiro and Tashiro, J. Neurochemistry, 77, 1425-1432 (2007)]. In order to elucidate the reason why phosphate ion retards the amyloid fibril formation, we examined the preferential binding sites of phosphate ion to Aβ 1-40 using chemic Read More

Aquaporin Z (AqpZ) is a typical orthodox aquaporin with 6 transmembrane domains and five connecting loops. In order to express this complex membrane protein efficiently, E. coli cell-free expression system was employed as an alternative to produce aquaporin Z. Using different fusion vectors containing AqpZ gene, the expression level of fusion proteins in cell-free system varied from 7.97 to 578.35 μg/ml, while 7.34 to Read More

Tumor necrosis factor-α (TNF-α) is a glycoprotein hormone with important functions in inflammation and apoptosis. It plays a significant role as a pro-inflammatory cytokine in the defense against viral, bacterial and parasitic infections and autoimmune disorders. Furthermore, it influences energy homeostasis and has an anorexigenic effect on the hypothalamus. TNF-α has also been shown to be involved in the pathogenesi Read More

Oxazepam and lorazepam inhibit the adenosine deaminase (ADA) differently. In the case of lorazepam temperature increment causes an increase in the inhibition potency whereas higher temperature reduces the inhibitory effect of oxazepam; which proposes the overall profounder structural changes in the case of lorazepam relative to those caused by oxazepam.

Comparison between the BAD complexes indicated that BAD all docks a hydrophobic surface of PKAc regardless of its phosphorylation. PKAc may prevent Bcl-xL from rebinding to BAD by phosphorylating human BAD at Ser118; whereas human BAD is phosphorylated on Ser75 in a BAD-Bcl-xL complex, resulting in the dissociation of BAD.

A lectin specific for glucuronic acid and galacturonic acid has been isolated from seeds of the French bean Phaseolus vulgaris using a procedure that involved affinity chromatography on Affi-gel blue gel, fast protein liquid chromatography (FPLC)-ion exchange chromatography on Mono S, and FPLC-gel filtration on Superdex 200. The lectin was comprised of two 32-kDa subunits with substantial N-terminal sequence similarity to Read More

The three new Au (III), Pt (II) and Pd (II) complexes with pentapeptide glycyl-glycyl-L-methyonyl-glycylglycine have been synthesized, isolated, and spectroscopically and structurally elucidated in solution and in the solid-state. Solid-state linear-dichroic infrared (IR-LD) spectroscopy of oriented colloids in a nematic liquid crystal host, 1H- and 13CNMR, TGA and DSC, UV-VIS spectroscopy, EPR, ESI- and FAB- mass spectrometry an Read More

Cathepsin L (ctsl), a lysosomal cyteine protease over expressed and secreted by cancer cells, has been implicated in a number of physiological and pathological processes including tumor cell proliferation and metastasis. In the present study we demonstrate that an unknown mRNA of human origin (Gene Bank accession number AF 217997) is a splice variant of human cathepsin L mRNA (hCATL A IV) and encodes a truncated f Read More

In this study, we used two categories of molecular descriptors as CODESSA and DPPS (divided physicochemical property scores of amino acids) to parameterize structural characteristics of 2015 human amphiphysin SH3 domainbinding decapeptides at atom and residue levels. Based upon that, several robust quantitative structure-affinity relationship (QSAR) models were then constructed using partial least squares regression (P Read More

Lipases share an overall α/β hydrolase fold structure characteristic of serine hydrolases. Nevertheless, each lipases group possesses its characteristic 3-D structure and catalytic properties. The purified N-terminal truncated forms of a pancreatic (from ostrich) and a fungal (from Rhizopus oryzae, ROL32) (sayari et al., 2005) lipases displayed much lower activities as compared to the native proteins. The aim of this Read More

The superoxide anion radical is a highly reactive toxic species produced during metabolic processes. Several copper (II) complexes with peptides are known to show superoxide dismutase (SOD) activity but those having a peptide with a non-natural amino acid are limited. The synthesis of HisAibGly peptide and its complexation with copper (II) ions has been reported. The interaction of the synthetic peptide with Cu(II) was st Read More

DNA ligase is an important enzyme and it plays vital role in the replication and repair; also catalyzes nick joining between adjacent bases of DNA. The NAD+ dependent DNA ligase is selectively present in eubacteria and few viruses; but missing in humans. Homology modeling was used to generate 3-D structure of NAD+ dependent DNA ligase (LigA) of Mycobacterium tuberculosis using the known template (PDB: 2OWO). F Read More