(Below N is a link to NCBI taxonomic web page and E link to ESTHER at designed phylum.) > cellular organisms: NE > Bacteria: NE > Terrabacteria group: NE > Firmicutes: NE > Bacilli: NE > Bacillales: NE > Paenibacillaceae: NE > Paenibacillus: NE > Paenibacillus sp. R4: NE
LegendThis sequence has been compared to family alignement (MSA) red => minority aminoacid blue => majority aminoacid color intensity => conservation rate title => sequence position(MSA position)aminoacid rate Catalytic site Catalytic site in the MSA MPNVDMPLSQLQDYKPELTNETDFDLFWDNAKALSNQKPLHAQVNLVQDY PLKSISIYDVVYDGADGTPIHGWYVTPKGEHQPGSLPVLVKYHGYSGNRG YPNELLQWASMGMAALAIDVRGQGGVTPDRAEYPQGGIPGWMTLGILDPA SYYYKQVYLDCIRALDFVCSREEVDASRIAVYGGSQGGGLALAAAGLDSR PKLALPVFPFLCHFRRSVEIHASGPYVEIKNWFRRYDPEHRQEEQVYRTL SYFDGMNMASRIKARTLMAITLQDITCPPSTCFAAYNHLAGPKEVRLYHD YGHEGLPFHEEAMMRFIEAYL
Reference
Title: Crystal structure and functional characterization of a cold-active acetyl xylan esterase (PbAcE) from psychrophilic soil microbe Paenibacillus sp Park SH, Yoo W, Lee CW, Jeong CS, Shin SC, Kim HW, Park H, Kim KK, Kim TD, Lee JH Ref: PLoS ONE, 13:e0206260, 2018 : PubMed
Cold-active acetyl xylan esterases allow for reduced bioreactor heating costs in bioenergy production. Here, we isolated and characterized a cold-active acetyl xylan esterase (PbAcE) from the psychrophilic soil microbe Paenibacillus sp. R4. The enzyme hydrolyzes glucose penta-acetate and xylan acetate, reversibly producing acetyl xylan from xylan, and it shows higher activity at 4 degrees C than at 25 degrees C. We solved the crystal structure of PbAcE at 2.1-A resolution to investigate its active site and the reason for its low-temperature activity. Structural analysis showed that PbAcE forms a hexamer with a central substrate binding tunnel, and the inter-subunit interactions are relatively weak compared with those of its mesophilic and thermophilic homologs. PbAcE also has a shorter loop and different residue composition in the beta4-alpha3 and beta5-alpha4 regions near the substrate binding site. Flexible subunit movements and different active site loop conformations may enable the strong low-temperature activity and broad substrate specificity of PbAcE. In addition, PbAcE was found to have strong activity against antibiotic compound substrates, such as cefotaxime and 7-amino cephalosporanic acid (7-ACA). In conclusion, the PbAcE structure and our biochemical results provide the first example of a cold-active acetyl xylan esterase and a starting template for structure-based protein engineering.
Acetyl xylan esterase from Paenibacillus sp. R4
