Department of Microbiology, Faculty of Biology, University of Barcelona, Barcelona, Spain.
Appl Environ Microbiol. 2012 Mar;78(6):1724-32. doi: 10.1128/AEM.06332-11. Epub 2012 Jan 6.
Bacterial lipases constitute the most important group of biocatalysts for synthetic organic chemistry. Accordingly, there is substantial interest in developing new valuable lipases. Considering the lack of information concerning the lipases of the genus Rhodococcus and taking into account the interest raised by the enzymes produced by actinomycetes, a search for putative lipase-encoding genes from Rhodococcus sp. strain CR-53 was performed. We isolated, cloned, purified, and characterized LipR, the first lipase described from the genus Rhodococcus. LipR is a mesophilic enzyme showing preference for medium-chain-length acyl groups without showing interfacial activation. It displays good long-term stability and high tolerance for the presence of ions and chemical agents in the reaction mixture. Amino acid sequence analysis of LipR revealed that it displays four unique amino acid sequence motifs that clearly separate it from any other previously described family of bacterial lipases. Using bioinformatics tools, LipR could be related only to several uncharacterized putative lipases from different bacterial origins, all of which display the four blocks of consensus amino acid sequence motifs that contribute to define a new family of bacterial lipases, namely, family X. Therefore, LipR is the first characterized member of the new bacterial lipase family X. Further confirmation of this new family of lipases was performed after cloning Burkholderia cenocepacia putative lipase, bearing the same conserved motifs and clustering in family X. Interestingly, all lipases grouping in the new bacterial lipase family X display a Y-type oxyanion hole, a motif conserved in the Candida antarctica lipase clan but never found among bacterial lipases. This observation contributes to confirm that LipR and its homologs belong to a new family of bacterial lipases.
细菌脂肪酶构成了合成有机化学中最重要的一类生物催化剂。因此，人们对开发新的有价值的脂肪酶有很大的兴趣。考虑到有关罗德里格斯氏菌属脂肪酶的信息缺乏，并考虑到放线菌产生的酶引起的兴趣，我们从罗德里格斯氏菌 CR-53 菌株中寻找潜在的脂肪酶编码基因。我们分离、克隆、纯化并表征了 LipR，这是罗德里格斯氏菌属中描述的第一种脂肪酶。LipR 是一种嗜温酶，对中链长酰基具有偏好性，而不表现界面激活。它显示出良好的长期稳定性和对反应混合物中离子和化学试剂的高耐受性。LipR 的氨基酸序列分析表明，它显示出四个独特的氨基酸序列基序，使其与任何其他先前描述的细菌脂肪酶家族明显分离。使用生物信息学工具，LipR 只能与来自不同细菌来源的几个未表征的推定脂肪酶相关，所有这些酶都显示出有助于定义新的细菌脂肪酶家族的四个保守氨基酸序列基序块，即家族 X。因此，LipR 是新的细菌脂肪酶家族 X 的第一个特征成员。在克隆伯克霍尔德氏菌属假单胞菌推定脂肪酶后，对这个新的细菌脂肪酶家族进行了进一步确认，该酶具有相同的保守基序，并聚类在家族 X 中。有趣的是，所有归类于新的细菌脂肪酶家族 X 的脂肪酶都显示出 Y 型氧阴离子孔，这是一个在南极假丝酵母脂肪酶族中保守的基序，但从未在细菌脂肪酶中发现过。这一观察结果有助于确认 LipR 及其同源物属于新的细菌脂肪酶家族。
