PT  - JOURNAL ARTICLE
AU  - Jiujun Cheng
AU  - Tatyana Romantsov
AU  - Katja Engel
AU  - Andrew C. Doxey
AU  - David R. Rose
AU  - Josh D. Neufeld
AU  - Trevor Charles
TI  - Functional metagenomics reveals novel β-galactosidases not predictable from gene sequences
AID  - 10.1101/047167
DP  - 2016 Jan 01
TA  - bioRxiv
PG  - 047167
4099  - http://biorxiv.org/content/early/2016/04/05/047167.short
4100  - http://biorxiv.org/content/early/2016/04/05/047167.full
AB  - A soil metagenomic library carried in pJC8 (an IncP cosmid) was used for functional complementation for β-galactosidase activity in both α-Proteobacteria (Sinorhizobium meliloti) and γ-Proteobacteria (Escherichia coli). One β-galactosidase, encoded by overlapping clones selected in both hosts, was identified as a member of glycoside hydrolase family 2. ORFs obviously encoding possible β-galactosidases were not identified in 19 other clones that were only able to complement S. meliloti. Based on low sequence similarity to known glycoside hydrolases but not β-galactosidases, three ORFs were examined further. Biochemical analysis confirmed that all encoded β-galactosidase activity. Bioinformatic and structural modeling implied that Lac161_ORF10 protein represented a novel enzyme family with a five-bladed propeller glycoside hydrolase domain.CmR(chloramphenicol resistant)GmR(gentamicin resistant)KmR(kanamycin resistant)NmR(neomycin resistant)RifR(rifampicin resistant)SmR(streptomycin resistant)TcR(tetracycline resistant)