title: Molecular cloning and characterization of a novel SGNH arylesterase from the goat rumen contents.
abstract: An esterase-encoding gene, estR5, was directly obtained from the genomic DNA of goat rumen contents. The 555-bp full-length gene encodes a 184-residue polypeptide (EstR5) without putative signal peptide. Deduced EstR5 shared the highest identity (50%) to a putative arylesterase from Ruminococcaceae bacterium D16. Phylogenetic analysis indicated that EstR5 was closely related with microbial esterases of gastrointestinal source. A comparison of the conserved motifs shared with GDSL proteins revealed that EstR5 could be grouped into the GDSL family and was further classified into the subfamily of SGNH hydrolases. The gene estR5 was expressed in Escherichia coli BL21 (DE3) and purified to electrophoretic homogeneity. Recombinant EstR5 exhibited highest catalytic efficiency towards α-naphthyl acetate followed by phenyl acetate and p-nitrophenyl acetate and had no activity towards PNP esters with acyl chains longer than C8. The enzyme exhibited optimal activity at around 60°C and pH 8.0, was stable at pH ranging from 6.0 to 11.0 and was slightly activated by detergent Tween, Nonidet P-40, and Triton X-100. These properties suggest that EstR5 has great potential for basic research and industrial applications. To our knowledge, this is the first arylesterase obtained from rumen microenvironment.
authors.affiliation: Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, No. 12 Zhongguancun South Street, Beijing, 100081, People's Republic of China.
authors.forename: Guozeng
authors.initials: G
authors.lastname: Wang
authors.forename: Kun
authors.initials: K
authors.lastname: Meng
authors.forename: Huiying
authors.initials: H
authors.lastname: Luo
authors.forename: Yaru
authors.initials: Y
authors.lastname: Wang
authors.forename: Huoqing
authors.initials: H
authors.lastname: Huang
authors.forename: Pengjun
authors.initials: P
authors.lastname: Shi
authors.forename: Xia
authors.initials: X
authors.lastname: Pan
authors.forename: Peilong
authors.initials: P
authors.lastname: Yang
authors.forename: Bin
authors.initials: B
authors.lastname: Yao
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D002265:Carboxylic Ester Hydrolases / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D004795:Enzyme Stability; D006041:Goats / Q000382:microbiology*; D006094:Gram-Positive Bacteria / Q000145:classification / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D007700:Kinetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D012417:Rumen / Q000382:microbiology*; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; D002265:Carboxylic Ester Hydrolases; C019734:arylesterase