Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Albino mutants of Streptomyces glaucescens tyrosinase.

ABSTRACT: Site-directed mutagenesis was used to determine the functional role of several residues of Streptomyces glaucescens tyrosinase. Replacement of His-37, -53, -193 or -215 by glutamine yields albino phenotypes, as determined by expression on melanin-indicator plates. The purified mutant proteins display no detectable oxy-enzyme and increased Cu lability at the binuclear active site. The carbonyl derivatives of H189Q and H193Q luminesce, with lambda max. displaced more than 25 nm to a longer wavelength compared with native tyrosinase. The remaining histidine mutants display no detectable luminescence. The results are consistent with these histidine residues (together with His-62 and His-189 reported earlier) acting as Cu ligands in the Streptomyces glaucescens enzyme. Conservative substitution of the invariant Asn-190 by glutamine also gives an albino phenotype, no detectable oxy-enzyme and labilization of active-site Cu. The luminescence spectrum of carbonyl-N190Q, however, closely resembles that of the native enzyme under conditions promoting double Cu occupancy of the catalytic site. A critical role for Asn-190 in active-site hydrogen-bonding interactions is proposed.

SUBMITTER: Jackman MP

PROVIDER: S-EPMC1149969 | biostudies-other | 1991 Mar

REPOSITORIES: biostudies-other

ACCESS DATA

Json Xml

Similar Datasets

Enantioselective sulfoxidation using <i>Streptomyces glaucescens</i> GLA.0.

Project description:Asymmetric oxidation of prochiral sulfides is a direct means for production of enantiopure sulfoxides which are important in organic synthesis and the pharmaceutical industry. In the present study, Streptomyces glaucescens GLA.0 was employed for stereoselective oxidation of prochiral sulfides. Growing cells selectively catalyzed the oxidation of phenyl methyl sulfide to the corresponding sulfoxide. Only very little overoxidation was observed, resulting in minor amounts of the unwanted sulfone. Addition of isopropyl alcohol as a co-solvent, time of substrate addition and composition of the reaction media resulted in enhanced phenyl methyl sulfide biotransformation. The concentration of the undesired by-product (sulfone) was as low as 4% through the reaction course under optimal reaction conditions. The results show that S. glaucescens GLA.0 is a promising whole-cell biocatalyst for preparing highly enantiopure (R)-phenyl methyl sulfoxide in high yield (90%) with an enantiomeric excess (ee) exceeding 99%.

| S-EPMC9056634 | biostudies-literature

Streptomyces glaucescens

Project description:Streptomyces glaucescens overview

| PRJNA1020227 | ENA

Chromosomal deletion and rearrangement in Streptomyces glaucescens.

Project description:The Streptomyces glaucescens genome frequently undergoes gross genomic rearrangement events which result in the deletion of extremely large segments of chromosomal DNA. The structure and origin of the DNA forming the novel junctions arising from five of these deletion events are described. Only one junction proved to be the result of a relatively simple event; the remainder were more complex, with one involving DNA which originated from at least five distinct loci. In three of the investigated cases, DNA sequences present in the junctions appeared to have resulted from the duplication of previously unique sequences, suggesting that duplication of chromosomal segments may be an important factor in genetic instability. The nucleotide sequences surrounding these junctions and their respective wild-type termini were determined.

| S-EPMC207968 | biostudies-other

Transcript profiling of Arabidopsis albino msh1 mutants

Project description:The soybean msh1 RNAi transgenic line show various growth phenotype. We use microarray analysis to characterize gene expression pattern for two of the phenotypes - variegation and stunted growth.

2011-11-29 | GSE30281 | GEO

Streptomyces glaucescens strain:GLA.O

Project description:Streptomyces glaucescens GLA.O Genome sequencing

| PRJNA260814 | ENA

Purification and characterization of a nutritionally controlled endodeoxyribonuclease from Streptomyces glaucescens.

Project description:Streptomyces glaucescens has a DNAase whose synthesis is under nutritional control. We have purified this enzyme to apparent homogeneity by phosphocellulose chromatography followed by heparin-agarose, Cibacron Blue F3-GA-Sepharose and Sephadex G-75 chromatography and MonoQ f.p.l.c. The enzyme had an apparent Mr of 39,600 and a pI of approx. 8.15. The Mr of the native enzyme estimated by gel chromatography was 49,000. The DNAase had a pH optimum of 7.5 and an absolute requirement for bivalent cations in the reaction buffer. It was inhibited by high salt concentrations, chelating agents or phosphate-containing compounds and was stimulated by dimethyl sulphoxide. The activity was greatly diminished unless dithiothreitol or 2-mercaptoethanol was included in the reaction mixture. Reagents such as Hg2+ or iodoacetate strongly inhibited the enzyme. The nuclease hydrolysed both double-stranded and single-stranded DNA, showing greater affinity for double-stranded DNA, and no detectable hydrolysis of RNA. The enzyme produced nicks in double-stranded DNA, generating 3'-hydroxy and 5'-phosphate termini, and degraded circular DNA.

| S-EPMC1130666 | biostudies-other

Biochemical Characterization of GacI, a Bifunctional Glycosyltransferase-Phosphatase Enzyme Involved in Acarbose Biosynthesis in <i>Streptomyces glaucescens</i> GLA.O.

Project description:Acarbose, a pseudotetrasaccharide produced by several strains of Actinoplanes and Streptomyces, is an α-glucosidase inhibitor clinically used to control type II diabetes. Bioinformatic analysis of the biosynthetic gene clusters of acarbose in Actinoplanes sp. SE50/110 (the acb cluster) and Streptomyces glaucescens GLA.O (the gac cluster) revealed their distinct genetic organizations and presumably biosynthetic pathways. However, to date, only the acarbose pathway in the SE50/110 strain has been extensively studied. Here, we report that GacI, one of the proteins that appear to be different between the two pathways, is a bifunctional glycosyltransferase family 5 (GT5)-phosphatase (PP) enzyme that functions at two different steps in acarbose biosynthesis in S. glaucescens GLA.O. In the acb pathway, the GT and the PP reactions are performed by two different enzymes. Truncated GacI proteins having only the GT or the PP domain showed comparable catalytic activity with the full-length GacI, indicating that domain separation does not significantly affect their respective catalytic activity. GacI, which is widely distributed in many Streptomyces, represents the first example of naturally occurring GT5-PP bifunctional enzymes biochemically characterized.

| S-EPMC9669214 | biostudies-literature

Streptomyces glaucescens strain:SAI-055

Project description:Streptomyces glaucescens SAI-055 genome sequencing

| PRJNA1016924 | ENA

Albino mice with the point mutation at the tyrosinase locus show high cholesterol diet-induced NASH susceptibility.

Project description:Non-alcoholic fatty liver disease (NAFLD) constitutes a metabolic disorder with high worldwide prevalence and increasing incidence. The inflammatory progressive state, non-alcoholic steatohepatitis (NASH), leads to liver fibrosis and carcinogenesis. Here, we evaluated whether tyrosinase mutation underlies NASH pathophysiology. Tyrosinase point-mutated B6 (Cg)-Tyrc-2J/J mice (B6 albino) and C57BL/6J black mice (B6 black) were fed with high cholesterol diet (HCD) for 10 weeks. Normal diet-fed mice served as controls. HCD-fed B6 albino exhibited high NASH susceptibility compared to B6 black, a phenotype not previously reported. Liver injury occurred in approximately 50% of B6 albino from one post HCD feeding, with elevated serum alanine aminotransferase and aspartate aminotransferase levels. NASH was induced following 2 weeks in severe-phenotypic B6 albino (sB6), but B6 black exhibited no symptoms, even after 10 weeks. HCD-fed sB6 albino showed significantly higher mortality rate. Histological analysis of the liver revealed significant inflammatory cell and lipid infiltration and severe fibrosis. Serum lipoprotein analysis revealed significantly higher chylomicron and very low-density lipoprotein levels in sB6 albino. Moreover, significantly higher small intestinal lipid absorption and lower fecal lipid excretion occurred together with elevated intestinal NPC1L1 expression. As the tyrosinase point mutation represents the only genetic difference between B6 albino and B6 black, our work will facilitate the identification of susceptible genetic factors for NASH development and expand the understanding of NASH pathophysiology.

| S-EPMC8576022 | biostudies-literature

Novel Hypomorphic Alleles of the Mouse Tyrosinase Gene Induced by CRISPR-Cas9 Nucleases Cause Non-Albino Pigmentation Phenotypes.

Project description:Tyrosinase is a key enzyme in melanin biosynthesis. Mutations in the gene encoding tyrosinase (Tyr) cause oculocutaneous albinism (OCA1) in humans. Alleles of the Tyr gene have been useful in studying pigment biology and coat color formation. Over 100 different Tyr alleles have been reported in mice, of which ?24% are spontaneous mutations, ?60% are radiation-induced, and the remaining alleles were obtained by chemical mutagenesis and gene targeting. Therefore, most mutations were random and could not be predicted a priori. Using the CRISPR-Cas9 system, we targeted two distinct regions of exon 1 to induce pigmentation changes and used an in vivo visual phenotype along with heteroduplex mobility assays (HMA) as readouts of CRISPR-Cas9 activity. Most of the mutant alleles result in complete loss of tyrosinase activity leading to an albino phenotype. In this study, we describe two novel in-frame deletion alleles of Tyr, dhoosara (Sanskrit for gray) and chandana (Sanskrit for sandalwood). These alleles are hypomorphic and show lighter pigmentation phenotypes of the body and eyes. This study demonstrates the utility of CRISPR-Cas9 system in generating domain-specific in-frame deletions and helps gain further insights into structure-function of Tyr gene.

| S-EPMC4880214 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data