TY - JOUR
T1 - Structural-functional analysis reveals a specific domain organization in family GH20 hexosaminidases
AU - Val-Cid, Cristina
AU - Biarnés, Xevi
AU - Faijes, Magda
AU - Planas, Antoni
N1 - Publisher Copyright:
© 2015 Wilson et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
PY - 2015/5/29
Y1 - 2015/5/29
N2 - Hexosaminidases are involved in important biological processes catalyzing the hydrolysis of N-acetyl-hexosaminyl residues in glycosaminoglycans and glycoconjugates. The GH20 enzymes present diverse domain organizations for which we propose two minimal model architectures: Model A containing at least a non-catalytic GH20b domain and the catalytic one (GH20) always accompanied with an extra α-helix (GH20b-GH20-α), and Model B with only the catalytic GH20 domain. The large Bifidobacterium bifidum lacto-N-biosidase was used as a model protein to evaluate the minimal functional unit due to its interest and structural complexity. By expressing different truncated forms of this enzyme, we show that Model A architectures cannot be reduced to Model B. In particular, there are two structural requirements general to GH20 enzymes with Model A architecture. First, the non-catalytic domain GH20b at the N-terminus of the catalytic GH20 domain is required for expression and seems to stabilize it. Second, the substrate-binding cavity at the GH20 domain always involves a remote element provided by a long loop from the catalytic domain itself or, when this loop is short, by an element from another domain of the multidomain structure or from the dimeric partner. Particularly, the lacto-N-biosidase requires GH20b and the lectin-like domain at the N- and C-termini of the catalytic GH20 domain to be fully soluble and functional. The lectin domain provides this remote element to the active site. We demonstrate restoration of activity of the inactive GH20b-GH20-α construct (model A architecture) by a complementation assay with the lectin-like domain. The engineering of minimal functional units of multidomain GH20 enzymes must consider these structural requirements.
AB - Hexosaminidases are involved in important biological processes catalyzing the hydrolysis of N-acetyl-hexosaminyl residues in glycosaminoglycans and glycoconjugates. The GH20 enzymes present diverse domain organizations for which we propose two minimal model architectures: Model A containing at least a non-catalytic GH20b domain and the catalytic one (GH20) always accompanied with an extra α-helix (GH20b-GH20-α), and Model B with only the catalytic GH20 domain. The large Bifidobacterium bifidum lacto-N-biosidase was used as a model protein to evaluate the minimal functional unit due to its interest and structural complexity. By expressing different truncated forms of this enzyme, we show that Model A architectures cannot be reduced to Model B. In particular, there are two structural requirements general to GH20 enzymes with Model A architecture. First, the non-catalytic domain GH20b at the N-terminus of the catalytic GH20 domain is required for expression and seems to stabilize it. Second, the substrate-binding cavity at the GH20 domain always involves a remote element provided by a long loop from the catalytic domain itself or, when this loop is short, by an element from another domain of the multidomain structure or from the dimeric partner. Particularly, the lacto-N-biosidase requires GH20b and the lectin-like domain at the N- and C-termini of the catalytic GH20 domain to be fully soluble and functional. The lectin domain provides this remote element to the active site. We demonstrate restoration of activity of the inactive GH20b-GH20-α construct (model A architecture) by a complementation assay with the lectin-like domain. The engineering of minimal functional units of multidomain GH20 enzymes must consider these structural requirements.
KW - Beta-n-acetylhexosaminidase
KW - Substrate-assisted catalysis
KW - Human-milk oligosaccharides
KW - Glycoside hydrolase
KW - Tay-sachs
KW - Biosidase
KW - Protein
KW - Inhibition
KW - Sequence
KW - Insight
UR - http://www.scopus.com/inward/record.url?scp=84932643053&partnerID=8YFLogxK
UR - https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=pure_univeritat_ramon_llull&SrcAuth=WosAPI&KeyUT=WOS:000355319400067&DestLinkType=FullRecord&DestApp=WOS_CPL
U2 - 10.1371/journal.pone.0128075
DO - 10.1371/journal.pone.0128075
M3 - Article
C2 - 26024355
AN - SCOPUS:84932643053
SN - 1932-6203
VL - 10
JO - PLoS ONE
JF - PLoS ONE
IS - 5
M1 - e0128075
ER -