Sandbox Reserved 1136

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{{Sandbox_Reserved_ESBS_2015}}
{{Sandbox_Reserved_ESBS_2015}}
==Structure and Functional aspects of Sucrose Synthase from ''Arabidopsis thaliana''==
==Structure and Functional aspects of Sucrose Synthase from ''Arabidopsis thaliana''==
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Sucrose Synthase 1 (EC:2.4.1.13), also known as the Sucrose-UDP glucolsyltransferase 1 or simply Susy, is a reversible enzyme allowing the synthesis or the degradation of Sucrose in ''Arabidopsis thaliana''. It belongs to the Glycosyltransferase subfamily 4 (GT4).
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Sucrose Synthase 1 (EC:2.4.1.13), also known as the Sucrose-UDP glucolsyltransferase 1, is a reversible enzyme allowing the synthesis or the degradation of Sucrose in ''Arabidopsis thaliana''. It is a 360 kDa tetramer and belongs to the Glycosyltransferase subfamily 4 (GT4).
<StructureSection scene='' size='340' side='right' caption='X-ray crystal structures of AtSus1, as a complex with UDP-glucose at 2.8-Å resolution and as a complex with UDP and fructose at 2.85-Å resolution'>
<StructureSection scene='' size='340' side='right' caption='X-ray crystal structures of AtSus1, as a complex with UDP-glucose at 2.8-Å resolution and as a complex with UDP and fructose at 2.85-Å resolution'>
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== Structural highlights ==
== Structural highlights ==
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Sucrose synthase is a homotetrameric enzyme.
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Sucrose synthase is normally a homotetrameric enzyme, but it can also exist in a dimer form
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<ref>Sucrose synthase oligomerization and F-actin association are regulated by sucrose concentration and phosphorylation. Duncan KA, Huber SC. Plant Cell Physiol. 2007 Nov; 48(11):1612-23.
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</ref>.
There are 6 SUS isoforms in Arabidopsis thaliana and all of them are structurally similar to sucrose phosphate synthases and glycogen synthases. <ref>Salerno GL, Curatti L. Origin of sucrose metabolism in higher plants: when, how and why? Trends Plant Sci. 2003 Feb</ref>.
There are 6 SUS isoforms in Arabidopsis thaliana and all of them are structurally similar to sucrose phosphate synthases and glycogen synthases. <ref>Salerno GL, Curatti L. Origin of sucrose metabolism in higher plants: when, how and why? Trends Plant Sci. 2003 Feb</ref>.
Each monomer is a chain of 808 residues which possesses four specific domains:
Each monomer is a chain of 808 residues which possesses four specific domains:
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• 1-127: N-Terminal regulatory domain involved in targeting <ref>Determination of structural requirements and probable regulatory effectors for membrane association of maize sucrose synthase 1. Hardin SC, Duncan KA, Huber SC. Plant Physiol. 2006</ref>. On this sequence, two serines can be phosphorylated, which enable a control of enzyme location <ref>Phosphorylation of sucrose synthase at serine 170: occurrence and possible role as a signal for proteolysis. Hardin SC, Tang GQ, Scholz A, Holtgraewe D, Winter H, Huber SC. Plant J. 2003</ref>.
• 1-127: N-Terminal regulatory domain involved in targeting <ref>Determination of structural requirements and probable regulatory effectors for membrane association of maize sucrose synthase 1. Hardin SC, Duncan KA, Huber SC. Plant Physiol. 2006</ref>. On this sequence, two serines can be phosphorylated, which enable a control of enzyme location <ref>Phosphorylation of sucrose synthase at serine 170: occurrence and possible role as a signal for proteolysis. Hardin SC, Tang GQ, Scholz A, Holtgraewe D, Winter H, Huber SC. Plant J. 2003</ref>.
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• 1-127: CTD: Cellular targeting domain
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• 1-127: CTD: Cellular targeting domain.
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• 157-276: EPBD: ENOD40 peptide-binding domain. This domain has a role in the regulation of the enzyme.
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• 157-276: EPBD: ENOD40 peptide-binding domain. This domain has a role in the regulation of the enzyme. It is able to bind a potassium ion.
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• 277-776 : GT-B glycosyltransferase domain. It contains the catlytic site.
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• 277-776 : GT-B glycosyltransferase domain. It contains the catlytic site and presents a characteristic Rossman-folding
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<ref>Glycosyltransferases: structures, functions, and mechanisms. Lairson LL, Henrissat B, Davies GJ, Withers SG. Annu Rev Biochem. 2008
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</ref>
• 776-808 : C-terminal extension. The length of this domain is variable depending of the SUS isoform.
• 776-808 : C-terminal extension. The length of this domain is variable depending of the SUS isoform.
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[[Image:Monomer_structure.jpg]]
[[Image:Monomer_structure.jpg]]
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== Structural highlights ==
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The GT-B domain is highly conserved in other isoforms and in the sucrose-phosphate synthase. This conservation reinforce the evolutionary relationship of those enzymes. Furthermore, this domain is also conserved in other species.
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== Regulation ==

Revision as of 12:16, 30 January 2016

This Sandbox is Reserved from 15/12/2015, through 15/06/2016 for use in the course "Structural Biology" taught by Bruno Kieffer at the University of Strasbourg, ESBS. This reservation includes Sandbox Reserved 1120 through Sandbox Reserved 1159.
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Structure and Functional aspects of Sucrose Synthase from Arabidopsis thaliana

Sucrose Synthase 1 (EC:2.4.1.13), also known as the Sucrose-UDP glucolsyltransferase 1, is a reversible enzyme allowing the synthesis or the degradation of Sucrose in Arabidopsis thaliana. It is a 360 kDa tetramer and belongs to the Glycosyltransferase subfamily 4 (GT4).

X-ray crystal structures of AtSus1, as a complex with UDP-glucose at 2.8-Å resolution and as a complex with UDP and fructose at 2.85-Å resolution

Drag the structure with the mouse to rotate


References

• UniProt entry: P49040

• Brenda entry : 2.4.1.13

  1. ↑ Salerno GL, Curatti L Origin of sucrose metabolism in higher plants: when, how and why? Trends Plant Sci. 2003 Feb
  2. ↑ Baroja-Fernández, E., Muñoz, F.J., Saikusa, T., Rodríguez-López, M., Akazawa, T. and Pozueta-Romero, J. Sucrose synthase catalyzes the de novo production of ADPglucose linked to starch biosynthesis in heterotrophic tissues of plants. Plant Cell Physiol.
  3. ↑ Sucrose synthase oligomerization and F-actin association are regulated by sucrose concentration and phosphorylation. Duncan KA, Huber SC. Plant Cell Physiol. 2007 Nov; 48(11):1612-23.
  4. ↑ Salerno GL, Curatti L. Origin of sucrose metabolism in higher plants: when, how and why? Trends Plant Sci. 2003 Feb
  5. ↑ Determination of structural requirements and probable regulatory effectors for membrane association of maize sucrose synthase 1. Hardin SC, Duncan KA, Huber SC. Plant Physiol. 2006
  6. ↑ Phosphorylation of sucrose synthase at serine 170: occurrence and possible role as a signal for proteolysis. Hardin SC, Tang GQ, Scholz A, Holtgraewe D, Winter H, Huber SC. Plant J. 2003
  7. ↑ Glycosyltransferases: structures, functions, and mechanisms. Lairson LL, Henrissat B, Davies GJ, Withers SG. Annu Rev Biochem. 2008
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