التفاصيل البيبلوغرافية
| العنوان: |
Structure and mechanism of the ER-based glucosyltransferase ALG6 |
| المؤلفون: |
Joël S. Bloch, Giorgio Pesciullesi, Jérémy Boilevin, Kamil Nosol, Rossitza N. Irobalieva, Tamis Darbre, Markus Aebi, Anthony A. Kossiakoff, Jean-Louis Reymond, Kaspar P. Locher |
| المصدر: |
Nature, Nature. 579(7799):443-447 |
| سنة النشر: |
2020 |
| الوصف: |
In eukaryotic protein N-glycosylation, a series of glycosyltransferases catalyse the biosynthesis of a dolichylpyrophosphate-linked oligosaccharide before its transfer onto acceptor proteins1. The final seven steps occur in the lumen of the endoplasmic reticulum (ER) and require dolichylphosphate-activated mannose and glucose as donor substrates2. The responsible enzymes—ALG3, ALG9, ALG12, ALG6, ALG8 and ALG10—are glycosyltransferases of the C-superfamily (GT-Cs), which are loosely defined as containing membrane-spanning helices and processing an isoprenoid-linked carbohydrate donor substrate3,4. Here we present the cryo-electron microscopy structure of yeast ALG6 at 3.0 Å resolution, which reveals a previously undescribed transmembrane protein fold. Comparison with reported GT-C structures suggests that GT-C enzymes contain a modular architecture with a conserved module and a variable module, each with distinct functional roles. We used synthetic analogues of dolichylphosphate-linked and dolichylpyrophosphate-linked sugars and enzymatic glycan extension to generate donor and acceptor substrates using purified enzymes of the ALG pathway to recapitulate the activity of ALG6 in vitro. A second cryo-electron microscopy structure of ALG6 bound to an analogue of dolichylphosphate-glucose at 3.9 Å resolution revealed the active site of the enzyme. Functional analysis of ALG6 variants identified a catalytic aspartate residue that probably acts as a general base. This residue is conserved in the GT-C superfamily. Our results define the architecture of ER-luminal GT-C enzymes and provide a structural basis for understanding their catalytic mechanisms. |
| نوع الوثيقة: |
redif-article |
| اللغة: |
English |
| DOI: |
10.1038/s41586-020-2044-z |
| الإتاحة: |
https://ideas.repec.org/a/nat/nature/v579y2020i7799d10.1038_s41586-020-2044-z.html |
| رقم الأكسشن: |
edsrep.a.nat.nature.v579y2020i7799d10.1038.s41586.020.2044.z |
| قاعدة البيانات: |
RePEc |
