6MW8

UDP-galactose:glucoside-Skp1 alpha-D-galactosyltransferase with bound UDP and Manganese

Summary for 6MW8

• Entry DOI: 10.2210/pdb6mw8/pdb
• Descriptor: UDP-galactose:glucoside-Skp1 alpha-D-galactosyltransferase, MANGANESE (II) ION, URIDINE-5'-DIPHOSPHATE, ... (6 entities in total)
• Functional Keywords: glycosyltransferase, gt-a fold, transferase
• Biological source: Pythium ultimum
• Total number of polymer chains: 1
• Total formula weight: 30803.53

Authors

Kim, H.W.,Wood, Z.A.,West, C.M. (deposition date: 2018-10-29, release date: 2019-10-09, Last modification date: 2024-03-13)

Primary citation

Mandalasi, M.,Kim, H.W.,Thieker, D.,Sheikh, M.O.,Gas-Pascual, E.,Rahman, K.,Zhao, P.,Daniel, N.G.,van der Wel, H.,Ichikawa, H.T.,Glushka, J.N.,Wells, L.,Woods, R.J.,Wood, Z.A.,West, C.M.
A terminal alpha 3-galactose modification regulates an E3 ubiquitin ligase subunit in Toxoplasma gondii .
J.Biol.Chem., 295:9223-9243, 2020

PubMed Abstract: Skp1, a subunit of E3 Skp1/Cullin-1/F-box protein ubiquitin ligases, is modified by a prolyl hydroxylase that mediates O regulation of the social amoeba and the parasite The full effect of hydroxylation requires modification of the hydroxyproline by a pentasaccharide that, in , influences Skp1 structure to favor assembly of Skp1/F-box protein subcomplexes. In , the presence of a contrasting penultimate sugar assembled by a different glycosyltransferase enables testing of the conformational control model. To define the final sugar and its linkage, here we identified the glycosyltransferase that completes the glycan and found that it is closely related to glycogenin, an enzyme that may prime glycogen synthesis in yeast and animals. However, the enzyme catalyzes formation of a Galα1,3Glcα linkage rather than the Glcα1,4Glcα linkage formed by glycogenin. Kinetic and crystallographic experiments showed that the glycosyltransferase Gat1 is specific for Skp1 in and also in another protist, the crop pathogen The fifth sugar is important for glycan function as indicated by the slow-growth phenotype of Δ parasites. Computational analyses indicated that, despite the sequence difference, the glycan still assumes an ordered conformation that controls Skp1 structure and revealed the importance of nonpolar packing interactions of the fifth sugar. The substitution of glycosyltransferases in and by an unrelated bifunctional enzyme that assembles a distinct but structurally compatible glycan in is a remarkable case of convergent evolution, which emphasizes the importance of the terminal α-galactose and establishes the phylogenetic breadth of Skp1 glycoregulation.

PubMed: 32414843
DOI: 10.1074/jbc.RA120.013792

Experimental method

X-RAY DIFFRACTION (1.756 Å)