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Kong F,
Wang H,
Zhang E,
Sintchenko V,
Xiao M,
Sorrell TC,
Chen X,
Chen SC,
( 2010 ) secA1 gene sequence polymorphisms for species identification of Nocardia species and recognition of intraspecies genetic diversity. PMID : 20810768 : DOI : 10.1128/JCM.01113-10 PMC : PMC3020853 Abstract >>
Sequence analysis of the Nocardia essential secretory protein SecA1 gene (secA1) for species identification of 120 American Type Culture Collection (ATCC) and clinical isolates of Nocardia (16 species) was studied in comparison with 5'-end 606-bp 16S rRNA gene sequencing. Species determination by both methods was concordant for all 10 ATCC strains. secA1 gene sequencing provided the same species identification as 16S rRNA gene analysis for 94/110 (85.5%) clinical isolates. However, 40 (42.6%) isolates had sequences with <99.0% similarity to archived secA1 sequences for the species, including 29 Nocardia cyriacigeorgica (96.6 to 98.9% similarity) and 4 Nocardia veterana (91.5 to 98.9% similarity) strains. Discrepant species identification was obtained for 16 (14.5%) clinical isolates, including 13/23 Nocardia nova strains (identified as various Nocardia species by secA1 sequencing) and 1 isolate each of Nocardia abscessus (identified as Nocardia asiatica), Nocardia elegans (Nocardia africana), and Nocardia transvalensis (Nocardia blacklockiae); both secA1 gene sequence analysis and deduced amino acid sequence analysis determined the species to be different from those assigned by 16S rRNA gene sequencing. The secA1 locus showed high sequence diversity (66 sequence or genetic types versus 40 16S rRNA gene sequence types), which was highest for N. nova (14 secA1 sequence types), followed by Nocardia farcinica and N. veterana (n = 7 each); there was only a single sequence type among eight Nocardia paucivorans strains. The secA1 locus has potential for species identification as an adjunct to 16S rRNA gene sequencing but requires additional deduced amino acid sequence analysis. It may be a suitable marker for phylogenetic/subtyping studies.
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2. |
Badalamenti JP,
Erickson JD,
Salomon CE,
( 2016 ) Complete Genome Sequence of Streptomyces albus SM254, a Potent Antagonist of Bat White-Nose Syndrome Pathogen Pseudogymnoascus destructans. PMID : 27081146 : DOI : 10.1128/genomeA.00290-16 PMC : PMC4832174 Abstract >>
We sequenced and annotated the complete 7,170,504-bp genome of a novel secondary metabolite-producingStreptomycesstrain,Streptomyces albusSM254, isolated from copper-rich subsurface fluids at ~220-m depth within the Soudan Iron Mine (Soudan, MN, USA).
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3. |
Sugimori D,
Kano K,
Matsumoto Y,
( 2012 ) Purification, characterization, molecular cloning and extracellular production of a phospholipase A1 from Streptomyces albidoflavus NA297. PMID : 23772365 : DOI : 10.1016/j.fob.2012.09.006 PMC : PMC3678127 Abstract >>
A novel metal ion-independent phospholipase A1 of Streptomyces albidoflavus isolated from Japanese soil has been purified and characterized. The enzyme consists of a 33-residue N-terminal signal secretion sequence and a 269-residue mature protein with a deduced molecular weight of 27,199. Efficient and extracellular production of the recombinant enzyme was successfully achieved using Streptomyces lividans cells and an expression vector. A large amount (25 mg protein, 14.7 kU) of recombinant enzyme with high specific activity (588 U/mg protein) was purified by simple purification steps. The maximum activity was found at pH 7.2 and 50 �XC. At pH 7.2, the enzyme preferably hydrolyzed phosphatidic acid and phosphatidylserine; however, the substrate specificity was dependent on the reaction pH. The enzyme hydrolyzed lysophosphatidylcholine and not triglyceride and the p-nitrophenyl ester of fatty acids. At the reaction equilibrium, the molar ratio of released free fatty acids (sn-1:sn-2) was 63:37. The hydrolysis of phosphatidic acid at 50 �XC and pH 7.2 gave apparent V max and k cat values of 1389 �gmol min(-1) mg protein(-1) and 630 s(-1), respectively. The apparent K m and k cat/K m values were 2.38 mM and 265 mM(-1) s(-1), respectively. Mutagenesis analysis showed that Ser11 is essential for the catalytic function of the enzyme and the active site may include residues Ser216 and His218.
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4. |
( 2013 ) Crystal structure of phospholipase A1 from Streptomyces albidoflavus NA297. PMID : 23416196 : DOI : 10.1016/j.jsb.2013.02.003 Abstract >>
The metal-independent lipase from Streptomyces albidoflavus NA297 (SaPLA1) is a phospholipase A1 as it preferentially hydrolyzes the sn-1 acyl ester in glycerophospholipids, yielding a fatty acid and 2-acyl-lysophospholipid. The molecular mechanism underlying the substrate binding by SaPLA1 is currently unknown. In this study, the crystal structure of SaPLA1 was determined at 1.75? resolutions by molecular replacement. A structural similarity search indicated the highest structural similarity to an esterase from Streptomyces scabies, followed by GDSL family enzymes. The SaPLA1 active site is composed of a Ser-His dyad (Ser11 and His218), whereby stabilization of the imidazole is provided by the main-chain carbonyl oxygen of Ser216, a common variation of the catalytic triad in many serine hydrolases, where this carbonyl maintains the orientation of the active site histidine residue. The hydrophobic pocket and cleft for lipid binding are adjacent to the active site, and are approximately 13-15? deep and 14-16? long. A partial polyethylene glycol structure was found in this hydrophobic pocket.
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