Exploring nitrilase sequence space for enantioselective catalysis

被引：158

作者：

Robertson, DE ^{[1
]}

Chaplin, JA ^{[1
]}

DeSantis, G ^{[1
]}

Podar, M ^{[1
]}

Madden, M ^{[1
]}

Chi, E ^{[1
]}

Richardson, T ^{[1
]}

Milan, A ^{[1
]}

Miller, M ^{[1
]}

Weiner, DP ^{[1
]}

Wong, K ^{[1
]}

McQuaid, J ^{[1
]}

Farwell, B ^{[1
]}

Preston, LA ^{[1
]}

Tan, XQ ^{[1
]}

Snead, MA ^{[1
]}

Keller, M ^{[1
]}

Mathur, E ^{[1
]}

Kretz, PL ^{[1
]}

Burk, MJ ^{[1
]}

Short, JM ^{[1
]}

机构：

[1] Diversa Corp, San Diego, CA 92121 USA

来源：

APPLIED AND ENVIRONMENTAL MICROBIOLOGY | 2004年 / 70卷 / 04期

关键词：

D O I：

10.1128/AEM.70.4.2429-2436.2004

中图分类号：

Q81 [生物工程学（生物技术）]; Q93 [微生物学];

学科分类号：

071005 ; 0836 ; 090102 ; 100705 ;

摘要：

Nitrilases are important in the biosphere as participants in synthesis and degradation pathways for naturally occurring, as well as xenobiotically derived, nitriles. Because of their inherent enantioselectivity, nitrilases are also attractive as mild, selective catalysts for setting chiral centers in fine chemical synthesis. Unfortunately, <20 nitrilases have been reported in the scientific and patent literature, and because of stability or specificity shortcomings, their utility has been largely unrealized. In this study, 137 unique nitrilases, discovered from screening of >600 biotope-specific environmental DNA (eDNA) libraries, were characterized. Using culture-independent means, phylogenetically diverse genomes were captured from entire biotopes, and their genes were expressed heterologously in a common cloning host. Nitrilase genes were targeted in a selection-based expression assay of clonal populations numbering 106 to 1010 members per eDNA library. A phylogenetic analysis of the novel sequences discovered revealed the presence of at least five major sequence clades within the nitrilase subfamily. Using three nitrile substrates targeted for their potential in chiral pharmaceutical synthesis, the enzymes were characterized for substrate specificity and stereospecificity. A number of important correlations were found between sequence clades and the selective properties of these nitrilases. These enzymes, discovered using a high-throughput, culture-independent method, provide a catalytic toolbox for enantiospecific synthesis of a variety of carboxylic acid derivatives, as well as an intriguing library for evolutionary and structural analyses.

引用

页码：2429 / 2436

页数：8

共 34 条

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