Abstract
The crystal structure of α-glucosidase MalA from Sulfolobus solfataricus has been determined at 2.5 Å resolution. It provides a structural model for enzymes representing the major specificity in glycoside hydrolase family 31 (GH31), including α-glucosidases from higher organisms, involved in glycogen degradation and glycoprotein processing. The structure of MalA shows clear differences from the only other structure known from GH31, α-xylosidase YicI. MalA and YicI share only 23% sequence identity. Although the two enzymes display a similar domain structure and both form hexamers, their structures differ significantly in quaternary organization: MalA is a dimer of trimers, YicI a trimer of dimers. MalA and YicI also differ in their substrate specificities, as shown by kinetic measurements on model chromogenic substrates. In addition, MalA has a clear preference for maltose (Glc-α1,4-Glc), whereas YicI prefers isoprimeverose (Xyl-α1,6-Glc). The structural origin of this difference occurs in the -1 subsite where MalA residues Asp251 and Trp284 could interact with OH6 of the substrate. The structure of MalA in complex with β-octyl-glucopyranoside has been determined. It reveals Arg400, Asp87, Trp284, Met321 and Phe327 as invariant residues forming the +1 subsite in the GH31 α-glucosidases. Structural comparisons with other GH families suggest that the GH31 enzymes belong to clan GH-D.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1106-1124 |
| Number of pages | 19 |
| Journal | Journal of Molecular Biology |
| Volume | 358 |
| Issue number | 4 |
| DOIs | |
| State | Published - May 12 2006 |
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Keywords
- crystal structure
- glycoside hydrolase
- substrate specificity
- α-glucosidase
- α-xylosidase
ASJC Scopus subject areas
- Molecular Biology
Cite this
Structure of the Sulfolobus solfataricus α-Glucosidase : Implications for Domain Conservation and Substrate Recognition in GH31. / Ernst, Heidi A.; Lo Leggio, Leila; Willemoës, Martin; Leonard, Gordon; Blum, Paul H; Larsen, Sine.
In: Journal of Molecular Biology, Vol. 358, No. 4, 12.05.2006, p. 1106-1124.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Structure of the Sulfolobus solfataricus α-Glucosidase
T2 - Implications for Domain Conservation and Substrate Recognition in GH31
AU - Ernst, Heidi A.
AU - Lo Leggio, Leila
AU - Willemoës, Martin
AU - Leonard, Gordon
AU - Blum, Paul H
AU - Larsen, Sine
PY - 2006/5/12
Y1 - 2006/5/12
N2 - The crystal structure of α-glucosidase MalA from Sulfolobus solfataricus has been determined at 2.5 Å resolution. It provides a structural model for enzymes representing the major specificity in glycoside hydrolase family 31 (GH31), including α-glucosidases from higher organisms, involved in glycogen degradation and glycoprotein processing. The structure of MalA shows clear differences from the only other structure known from GH31, α-xylosidase YicI. MalA and YicI share only 23% sequence identity. Although the two enzymes display a similar domain structure and both form hexamers, their structures differ significantly in quaternary organization: MalA is a dimer of trimers, YicI a trimer of dimers. MalA and YicI also differ in their substrate specificities, as shown by kinetic measurements on model chromogenic substrates. In addition, MalA has a clear preference for maltose (Glc-α1,4-Glc), whereas YicI prefers isoprimeverose (Xyl-α1,6-Glc). The structural origin of this difference occurs in the -1 subsite where MalA residues Asp251 and Trp284 could interact with OH6 of the substrate. The structure of MalA in complex with β-octyl-glucopyranoside has been determined. It reveals Arg400, Asp87, Trp284, Met321 and Phe327 as invariant residues forming the +1 subsite in the GH31 α-glucosidases. Structural comparisons with other GH families suggest that the GH31 enzymes belong to clan GH-D.
AB - The crystal structure of α-glucosidase MalA from Sulfolobus solfataricus has been determined at 2.5 Å resolution. It provides a structural model for enzymes representing the major specificity in glycoside hydrolase family 31 (GH31), including α-glucosidases from higher organisms, involved in glycogen degradation and glycoprotein processing. The structure of MalA shows clear differences from the only other structure known from GH31, α-xylosidase YicI. MalA and YicI share only 23% sequence identity. Although the two enzymes display a similar domain structure and both form hexamers, their structures differ significantly in quaternary organization: MalA is a dimer of trimers, YicI a trimer of dimers. MalA and YicI also differ in their substrate specificities, as shown by kinetic measurements on model chromogenic substrates. In addition, MalA has a clear preference for maltose (Glc-α1,4-Glc), whereas YicI prefers isoprimeverose (Xyl-α1,6-Glc). The structural origin of this difference occurs in the -1 subsite where MalA residues Asp251 and Trp284 could interact with OH6 of the substrate. The structure of MalA in complex with β-octyl-glucopyranoside has been determined. It reveals Arg400, Asp87, Trp284, Met321 and Phe327 as invariant residues forming the +1 subsite in the GH31 α-glucosidases. Structural comparisons with other GH families suggest that the GH31 enzymes belong to clan GH-D.
KW - crystal structure
KW - glycoside hydrolase
KW - substrate specificity
KW - α-glucosidase
KW - α-xylosidase
UR - http://www.scopus.com/inward/record.url?scp=33745048293&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33745048293&partnerID=8YFLogxK
U2 - 10.1016/j.jmb.2006.02.056
DO - 10.1016/j.jmb.2006.02.056
M3 - Article
VL - 358
SP - 1106
EP - 1124
JO - Journal of Molecular Biology
JF - Journal of Molecular Biology
SN - 0022-2836
IS - 4
ER -