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The N-terminal amino acid sequence was analysed of 43 kDa polypeptide, component of the protein complex of PAF acetylhydrolase (PAF-AH) isolated from boar seminal plasma. Amino acid sequence of the 43 kDa did not show homology with the characteristic sequences of PAFAH isolated from other sources. However, 43 kDa showed a high homology with the characteristic sequences of IgG-binding proteins as well as with zona pellucida-binding adhesion proteins - zonadhesions. The results indicate that the isolated 43 kDa polypepfide belongs to the family of adhesion proteins, involved in the processes accompanying egg fertilization.
The complete cDNA and deduced amino-acid sequences of ribosomal proteins L34 (AmphiL34) and S29 (AmphiS29) from the amphioxus Branchiostoma belcheri tsingtauense were identified in this study. The AmphiL34 cDNA is 435 nucleotides in length and encodes a 118 amino-acid protein with calculated molecular mass of 13.6 kDa. It shares 53.6-67.5% amino-acid sequence identity with its eukaryotic counterparts including human, mouse, rat, pig, frog, catfish, fruit fly, mosquito, armyworm, nematode and yeast. The AmphiS29 cDNA comprises 453 nucleotides and codes for a 56 amino-acid protein with a calculated molecular mass of 6.6 kDa. It shows 66.1-78.6% amino-acid sequence identity to eukaryotic S29 proteins from human, mouse, rat, pig, zebrafish, seahorse, fruit fly, nematode, sea hare and yeast. AmphiL34 contains a putative nucleolar localization signal, while AmphiS29 has a zinc finger-like domain. A phylogenetic tree deduced from the conserved sequences of AmphiL34 and AmphiS29 and other known counterparts indicates that the positions of AmphiL34/AmphiS29 are intermediate between the vertebrate and invertebrate L34/S29. Southern blot analysis demonstrates the presence of one copy of the L34 gene and 2-3 copies of the S29 gene in the genome of the amphioxus B. belcheri tsingtauense. This is in sharp contrast to the existence of 7-9 copies of the L34 gene and 14-17 copies of the S29 gene in the rat genome. These date suggest that housekeeping genes like AmphiL34 and AmphiS29 have undergone large-scale duplication in the chordate lineage.
The comparative and evolutionary analysis of molecular data has allowed researchers to tackle biological questions that have long remained unresolved. The evolution of DNA and amino acid sequences can now be modeled accurately enough that the information conveyed can be used to reconstruct the past. The methods to infer phylogeny (the pattern of historical relationships among lineages of organisms and/or sequences) range from the simplest, based on parsimony, to more sophisticated and highly parametric ones based on likelihood and Bayesian approaches. In general, molecular systematics provides a powerful statistical framework for hypothesis testing and the estimation of evolutionary processes, including the estimation of divergence times among taxa. The field of molecular systematics has experienced a revolution in recent years, and, although there are still methodological problems and pitfalls, it has become an essential tool for the study of evolutionary patterns and processes at different levels of biological organization. This review aims to present a brief synthesis of the approaches and methodologies that are most widely used in the field of molecular systematics today, as well as indications of future trends and state-of-the-art approaches.
In this study, we report the cloning and characteristics of an adiponectin-like receptor gene from Bombyx mori (BmAdipoR) with highly conserved deduced amino-acid sequences and similar structure to the human adiponectin receptor (AdipoR). Structural analysis of the translated cDNA suggested it encoded a membrane protein with seven transmembrane domains. BmAdipoR was found to be expressed in multiple tissues and highly expressed in Malpighian tubules, fat body and testis. BmNPV (Bombyx morinucleopolyhedrovirus) bacmid system combined with confocal microscopy revealed that BmAdipoR was targeted to the cell membrane. We also found that infection with BmNPV did not have an effect on BmAdipoR mRNA quantity in the midgut of susceptible Bombyx moristrain (306) at 48 h, but BmAdipoR mRNA quantity increased significantly at 72 h. We concluded that BmAdipoR gene was a membrane protein ubiquitously expressed in Bombyx moritissues and that its expression was altered by treating with BmNPV.
The aim of the study was to monitor genetic diversity and antigenic changes in the genome of influenza A(H1N1)pdm09 viral isolates detected during the post-pandemic period in Poland. Clinical specimens obtained from three suspected cases of influenza were analysed by sequencing. Among the differences identified in amino acids sequences, nine substitutions were located within the antigenic HA1 sites and in five residues forming receptor-binding pocket. The HA(D222G) mutation was shown in the isolate Swine/Poland/134312/12 obtained from a mild case of the disease. It must be emphasized that, in general, clinically mild cases are caused by the viruses in which that specific mutation, i.e. haemagglutinin (D222G), does not occur.
Sexually transmitted diseases are a major cause of acute disease worldwide, and trichomoniasis is the most common and curable disease, generating more than 170 million cases annually worldwide. Trichomonas vaginalis is the causal agent of trichomoniasis and has the ability to destroy in vitro cell monolayers of the vaginal mucosa, where the phospholipases A2 (PLA2) have been reported as potential virulence factors. These enzymes have been partially characterized from the subcellular fraction S30 of pathogenic T. vaginalis strains. The main objective of this study was to purify a phospholipase A2 from T. vaginalis, make a partial characterization, obtain a partial amino acid sequence, and determine its enzymatic participation as hemolytic factor causing lysis of erythrocytes. Trichomonas S30, RF30 and UFF30 sub-fractions from GT-15 strain have the capacity to hydrolyze [2-14C-PA]-PC at pH 6.0. Proteins from the UFF30 sub-fraction were separated by affinity chromatography into two eluted fractions with detectable PLA A2 activity. The EDTA-eluted fraction was analyzed by HPLC using on-line HPLC-tandem mass spectrometry and two protein peaks were observed at 8.2 and 13 kDa. Peptide sequences were identified from the proteins present in the eluted EDTA UFF30 fraction; bioinformatic analysis using Protein Link Global Server charged with T. vaginalis protein database suggests that eluted peptides correspond a putative ubiquitin protein in the 8.2 kDa fraction and a phospholipase preserved in the 13 kDa fraction. The EDTA-eluted fraction hydrolyzed [2-14C-PA]-PC lyses erythrocytes from Sprague-Dawley in a time and dose-dependent manner. The acidic hemolytic activity decreased by 84% with the addition of 100 μM of Rosenthal’s inhibitor.
It is evident now that the gonadotropin-releasing hormone (GnRH) structure was already in existence very early in the evolution of animals and was co-opted in diverse ways to regulate reproduction. During 600 million years of animal evolution, the N and C termini of GnRH have been conserved as functional domains for binding and activating cognate receptors to accomplish its functions. About 400 millions years ago, a single substitution of the chiral amino acid in position 6 of GnRH in jawless fish by the achiral glycine facilitated a type II’ β-turn conformation of GnRH to allow spatially close interaction of functional domains of GnRH with receptors, in contrast to the interaction of more extended GnRH structures with their cognate receptors in earlier-evolved species. GnRH II was preconfigured to this conformation through intramolecular interactions, which accounts for its high binding affinity and total conservation of primary structure over 400 million years of evolution. It is very surprising and fascinating that the coordinated evolutionary selection of amino acids participating in binding GnRH has resulted in such perfection, that no substitution with a natural amino acid in any position improves binding potency.
Two serine proteinase inhibitors (ELTII and ELT1II) have been isolated from mature seeds of Echinocystis lobata by ammonium sulfate fractionation, methanol preci­pitation, ion exchange chromatography, affinity chromatography on immobilized anhydrotrypsin and HPLC. ELTI I and ELTI II consist of 33 and 29 amino-acid residues, respectively. The primary structures of these inhibitors are as follows: ELTI I KEEQRVCPRILMRCKRDSDCLAQCTCQQSGFCG ELTI II RVCPRILMRCKRDSDCLAQCTCQQSGFCG The inhibitors show sequence similarity with the squash inhibitor family. ELTI I differs from ELTI II only by the presence of the NH2-terminal tetrapeptide Lys- -Glu-Glu-Gln. The association constants (Ka) of F.LTI I and ELTI II with bovine-trypsin were determined to be 6.6 x 1010 M -1 and 3.1 x 1011 M -1, whereas the association constants of these inhibitors with cathepsin G were 1.2 x 107 M -1 and 1.1 x 107 M -1, respectively.
A trypsin inhibitor of Kazal type has been isolated from goose pancreas by affinity chromatography on immobilized anhydrotrypsin, anion exchange and reverse phase HPLC. It inhibits bovine β-trypsin with the association constant (Ka) of 5.99 x 10 M-1. The complete amino-acid sequence was determined following CNBr treatment. The protein comprised a total of 69 amino-acid residues, corresponding to a molecular mass of 7.7 kDa. The P1-P'1 reactive site bond of the inhibitor was localized at position Lys25-Met26. The amino-acid sequence of GPTI shows extremely high homology to that of other inhibitors isolated from pancreas of birds.
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