Search results for "specificity"

Cloning, tissue distribution, pharmacology and three-dimensional modelling of melanocortin receptors 4 and 5 in rainbow trout suggest close evolution…

2004

The rainbow trout (Oncorhynchus mykiss) is one of the most widely used fish species in aquaculture and physiological research. In the present paper, we report the first cloning, 3D (three-dimensional) modelling, pharmacological characterization and tissue distribution of two melanocortin (MC) receptors in rainbow trout. Phylogenetic analysis indicates that these receptors are orthologues of the human MC4 and MC5 receptors. We created 3D molecular models of these rainbow trout receptors and their human counterparts. These models suggest greater divergence between the two human receptors than between their rainbow trout counterparts. The pharmacological analyses demonstrated that ACTH (adreno…

Structural and functional consequences of the replacement of proximal residues Cys172 and Cys192 in the large subunit of ribulose-1,5-bisphosphate ca…

2008

Proximal Cys(172) and Cys(192) in the large subunit of the photosynthetic enzyme Rubisco (ribulose-1,5-bisphosphate carboxylase/oxygenase; EC 4.1.1.39) are evolutionarily conserved among cyanobacteria, algae and higher plants. Mutation of Cys(172) has been shown to affect the redox properties of Rubisco in vitro and to delay the degradation of the enzyme in vivo under stress conditions. Here, we report the effect of the replacement of Cys(172) and Cys(192) by serine on the catalytic properties, thermostability and three-dimensional structure of Chlamydomonas reinhardtii Rubisco. The most striking effect of the C172S substitution was an 11% increase in the specificity factor when compared wi…

A multidomain xylanase from a Bacillus sp. with a region homologous to thermostabilizing domains of thermophilic enzymes

1999

The gene xynC encoding xylanase C from Bacillus sp. BP-23 was cloned and expressed in Escherichia coli. The nucleotide sequence of a 3538 bp DNA fragment containing xynC gene was determined, revealing an open reading frame of 3258 bp that encodes a protein of 120,567 Da. A comparison of the deduced amino acid sequence of xylanase C with known beta-glycanase sequences showed that the encoded enzyme is a modular protein containing three different domains. The central region of the enzyme is the catalytic domain, which shows high homology to family 10 xylanases. A domain homologous to family IX cellulose-binding domains is located in the C-terminal region of xylanase C, whilst the N-terminal r…

Vibrio sinaloensis sp. nov., isolated from the spotted rose snapper, Lutjanus guttatus Steindachner, 1869.

2008

Nine bacterial strains were studied by means of rep-PCR, 16S rRNA gene sequence analysis, DNA-DNA hybridization and physiological characterization. Typing analysis by means of rep-PCR showed that all nine strains were highly homogeneous, with similarities above 94 %. The strains were isolated from the same geographical area (Mazatlan, Sinaloa state, Mexico) and the same type of host (cultured rose snapper, Lutjanus guttatus), although from different individuals and organs. Comparison of the almost-complete 16S rRNA gene sequences of five strains showed that they belonged to the genus Vibrio and are closely related to the type strains of Vibrio brasiliensis and Vibrio hepatarius, with simila…

Complex evolution of tandem-repetitive DNA in the Chironomus thummi species group.

1997

The subspecies Chironomus thummi thummi and C. t. piger display dramatic differences in the copy number and chromosomal localization of a tandemly repeated DNA family (Cla elements). In order to analyze the evolutionary dynamics of this repeat family, we studied the organization of Cla elements in the related outgroup species C. luridus. We find three different patterns of Cla element organization in C. luridus, showing that Cla elements may be either strictly tandem-repetitive or be an integral part of two higher-order tandem repeats (i.e., Hinf[lur] elements, Sal[lur] elements). All three types of Cla-related repeats are localized in the centromeres of C. luridus chromosomes. This suggest…

Interspecies comparison of neuroglobin, cytoglobin and myoglobin: Sequence evolution and candidate regulatory elements

2003

Neuroglobin and cytoglobin are two novel members of the vertebrate globin family. Their physiological role is poorly understood, although both proteins bind oxygen reversibly and may be involved in cellular oxygen homeostasis. Here we investigate the selective constraints on coding and non-coding sequences of the neuroglobin and cytoglobin genes in human, mouse, rat and fish. Neuroglobin and cytoglobin are highly conserved, displaying very low levels of non-synonymous nucleotide substitutions. An oxygen supply function predicts distinct modes of gene regulation, involving hypoxia-responsive transcription factors. To detect conserved candidate regulatory elements, we compared the neuroglobin…

Binding Sites for Neurotoxins and Cholinergic Ligands in Peripheral and Neuronal Nicotinic Receptors Studies with Synthetic Receptor Sequencesa

1995

Assay for O6-alkylguanine-DNA-alkyltransferase using oligonucleotides containing O6-methylguanine in a BamHI recognition site as substrate

1992

Abstract Double-stranded oligonucleotides, 40 bases in length containing an O 6 -methylguanine in a Bam HI restriction site, were developed as substrates for the determination of human O 6 -alkylguanine-DNA-alkyltransferase (AGT). The assay proved highly sensitive and quantitative. After incubation of the 5′-end-labeled oligonucleotides with cell homogenates of peripheral blood lymphocytes, the DNA was digested with Bam HI. Cleavage with this restriction enzyme did not occur in the O 6 -methylguanine-containing oligonucleotide unless the fragment was repaired. The cleaved oligonucleotide was separated from the intact parent oligonucleotide by reverse-phase high-performance liquid chromatogr…

Acquired C1 inhibitor (C1-INH) deficiency type II. Replacement therapy with C1-INH and analysis of patients' C1-INH and anti-C1-INH autoantibodies

1989

Abstract The response of two patients with autoantibody-mediated C1-inhibitor (C1-INH) deficiency to replacement therapy with C1-INH was studied over a period of 3 d. In patient 1 an acute attack of angioedema was successfully managed by infusion of 1,000 U of C1-INH concentrate. C1-INH function returned to normal levels within 30 min, while CH50 and C4 peaked after 6-7 h and C1 hemolytic activity reached 50-60% of normal after 3 d. Immediately after the injection an increase in C1-INH-anti-C1-INH complexes was observed. Based on NH2-terminal sequence analysis of the patients' Mr 96,000 C1-INH, it is concluded that this fragment is generated after cleavage of C1-INH in its active site by on…

Study of polymorphisms in the promoter region of ovine β-lactoglobulin gene and phylogenetic analysis among the Valle del Belice breed and other shee…

2012

The aim of this work was to sequence the promoter region of b-lactoglobulin (BLG) gene in four sheep breeds, in order to identify polymorphisms, infer and analyze haplotypes, and phylogenetic relationship among the Valle del Belice breed and the other three breeds considered as ancestors. Sequencing analysis and alignment of the obtained sequences showed the presence of 36 single nucleotide polymorphisms (SNPs) and one deletion. A total of 22 haplotypes found in ‘‘best’’ reconstruction were inferred considering the 37 polymorphic sites identified. Haplotypes were used for the reconstruction of a phylogenetic tree using the Neighbor-Joining algorithm. The number of polymorphisms identified s…