Cold-active β-Galactosidase from Arthrobacter sp. C2-2 Forms Compact 660kDa Hexamers: Crystal Structure at 1.9Å Resolution

107

Background: Deficiencies in ␤-D-galactosidase cause lysosomal storage diseases. Results: This is the first report to describe the crystal structure of human ␤-Gal. Human ␤-Gal is composed of a TIM barrel domain and two ␤-domains. Conclusion: The mutations were classified as mutations directly affecting the ligand recognition, mutations inside the protein core, or mutations located in the protein surface. Significance: Structural insights into lysosomal storage diseases mutations can be demonstrated.

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Crystal Structure of Human β-Galactosidase

Ohto¹,

Usui²,

Ochi

et al. 2012

107

“…In addition to the bioinformatics analysis, this non-universality was also suggested by crystal structures of ␤-galactosidases from Arthrobacter sp. (41) and Kluyveromyces lactis (42). Structural alignments reveal that the allolactose synthesis motif residues are not conserved in the two enzymes and neither enzyme has a structure homologous to the active site loop of the E. coli enzyme.…”

Section: Discussionmentioning

confidence: 99%

Structural Explanation for Allolactose (lac Operon Inducer) Synthesis by lacZ β-Galactosidase and the Evolutionary Relationship between Allolactose Synthesis and the lac Repressor

Wheatley

Jancewicz

et al. 2013

Background: Synthesis of allolactose (lac operon inducer) from lactose requires a site for clasping glucose as an acceptor on ␤-galactosidase. Results: The structure of the glucose site was defined, and its evolutionary conservation was determined. Conclusion: The glucose binding site defines an "allolactose synthesis motif" that is co-selected with lac repressors. Significance: Novel insights into evolutionary adaptations for regulation by allolactose are presented.

“…Taking E. coli ␤-gal as an example, Trp-999 at the ϩ1 site was reported to contribute to stabilizing the direction of ϩ1 glucose by stacking interactions, to facilitate the cleavage of the ␤(1,4)-galactosyl linkage (43). In the other two GH-2 members, C221 ␤-gal and K. lactis ␤-gal, Trp-999 of E. coli ␤-gal is substituted by Cys-999 and Cys-1001, respectively, which were proposed to have an influence on substrate binding and activity (23,24). As for A4 ␤-gal and B. circulans sp.…”

Section: Resultsmentioning

confidence: 99%

Structural Insights into the Substrate Specificity of Streptococcus pneumoniae β(1,3)-Galactosidase BgaC

Wang¹,

Wang²,

Jiang

et al. 2012

Background:Streptococcus pneumoniae BgaC is a GH-35 ␤-galactosidase of specific activity toward ␤(1,3)-linked galactose and N-acetylglucosamine. Results: Three aromatic residues, Trp-240, Trp-243, and Tyr-455, determine the substrate specificity of BgaC. Conclusion: BgaC and other GH-35 ␤-galactosidases adopt a similar domain organization and catalytic mechanism. Significance: Provided is the first structural insight into the substrate specificity of ␤-galactosidase toward the ␤(1,3)-linked galactosyl bond.