Molecular and biochemical characterization of a novel xylanase from the symbiotic Sphingobacterium sp. TN19.
A xylanase-encoding gene, designated xynA19, was cloned from Sphingobacterium sp. TN19--a symbiotic bacterium isolated from the gut of Batocera horsfieldi larvae--and expressed in Escherichia coli BL21 (DE3). The full-length xynA19 (1,155 bp in length) encodes a 384-residue polypeptide (XynA19) containing a predicted signal peptide of 24 residues and a catalytic domain belonging to glycosyl hydrolase family 10 (GH 10). The deduced amino acid sequence of XynA19 is most similar (53.1% identity) to an endo-1,4-beta-xylanase from Prevotella bryantii B(1)4. Phylogenetic analysis of GH 10 Bacteroidia xylanases indicated that GH 10 xylanases from Sphingobacteria were separated into two clusters, and XynA19 is more closely related to the xylanases of Bacteroidia from gut or rumen than to those of Flavobacteria and Sphingobacteria from other sources. Recombinant XynA19 (r-XynA19) showed apparent optimal activity at pH 6.5 and 45 degrees C. Compared with thermophilic and mesophilic counterparts, r-XynA19 was more active at low temperatures, retaining >65% of its maximum activity at 20-28 degrees C and approximately 40% even at 10 degrees C, and modeling indicated that XynA19 has fewer hydrogen bonds and salt bridges. These properties suggest that XynA19 has various potential applications, especially in aquaculture and the food industry.
Zhou
Junpei
J
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.
Huang
Huoqing
H
Meng
Kun
K
Shi
Pengjun
P
Wang
Yaru
Y
Luo
Huiying
H
Yang
Peilong
P
Bai
Yingguo
Y
Zhou
Zhigang
Z
Yao
Bin
B
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D017931:DNA Primers; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D004275:DNA, Ribosomal / Q000235:genetics; D043364:Endo-1,4-beta Xylanases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D004926:Escherichia coli; D005822:Genetic Vectors; D007814:Larva / Q000382:microbiology; D008925:Mites / Q000382:microbiology; D008969:Molecular Sequence Data; D010957:Plasmids; D016133:Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D045249:Sphingobacterium / Q000201:enzymology* / Q000302:isolation & purification / Q000502:physiology; D013559:Symbiosis; D014934:Wood / Q000469:parasitology
D017931:DNA Primers; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D011994:Recombinant Proteins; D043364:Endo-1,4-beta Xylanases