کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1952119 1538426 2014 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Unusual carboxylesterase bearing a GGG(A)X-type oxyanion hole discovered in Paenibacillus barcinonensis BP-23
کلمات کلیدی
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی زیست شیمی
پیش نمایش صفحه اول مقاله
Unusual carboxylesterase bearing a GGG(A)X-type oxyanion hole discovered in Paenibacillus barcinonensis BP-23
چکیده انگلیسی


• Unusual carboxylesterase Est23 discovered in Paenibacillus barcinonensis BP-23.
• Est23 cloned, purified and characterized showing activity under moderate conditions.
• Est23 bears a GGG(X)-type oxyanion hole, interesting for resolution of tertiary alcohols.
• Est23 could be the first described member of a new family of bacterial lipases.

Strain Paenibacillus barcinonensis BP-23, previously isolated from Ebro's river delta (Spain), bears a complex hydrolytic system showing the presence of at least two enzymes with activity on lipidic substrates. EstA, a cell-bound B-type carboxylesterase from the strain was previously isolated and characterized. The gene coding for a second putative lipase, located upstream cellulase Cel5A, was obtained using a genome walking strategy and cloned in Escherichia coli for further characterization. The recombinant clone obtained displayed high activity on medium/short-chain fatty acid-derivative substrates. The enzyme, named Est23, was purified and characterized, showing maximum activity on pNP-caprylate (C8:0) or MUF-heptanoate (C7:0) under conditions of moderate temperature and pH. Although Est23 displays a GGG(A)X-type oxyanion hole, described as an important motif for tertiary alcohol ester resolution, neither conversion nor enantiomeric resolution of tertiary alcohols could be detected. Amino acid sequence alignment of Est23 with those of known bacterial lipase families and with closely related proteins suggests that the cloned enzyme does not belong to any of the described bacterial lipase families. A phylogenetic tree including Est23 and similar amino acid sequences showed that the enzyme belongs to a differentiated sequence cluster which probably constitutes a new family of bacterial lipolytic enzymes.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Biochimie - Volume 104, September 2014, Pages 108–116
نویسندگان
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