PDBsum entry: 1ga8

Transferase

PDB-id: 1ga8

Contents

Description

Header details

Header records

References

PROCHECK

Protein chain

278 a.a. *

Ligands

DEL

UPF

Metal ions

_MN

Waters ×191

* Residue conservation analysis

Tools

Clefts Calculation

PDB id:

1ga8

Name:

Transferase

Title:

Crystal structure of galacosyltransferase lgtc in complex with donor and acceptor sugar analogs.

Structure:

Galactosyl transferase lgtc. Chain: a. Engineered: yes. Mutation: yes

Source:

Neisseria meningitidis. Organism_taxid: 487. Gene: lgtc. Expressed in: escherichia coli bl21. Expression_system_taxid: 511693.

UniProt:

P96945 (P96945_NEIME)

Seq:

Struc:

Seq:

311 a.a.

Struc:

278 a.a.*

Key:	PfamA domain
Secondary structure	CATH domain

* PDB and UniProt seqs differ at 4 residue positions (black crosses)

Resolution:

2.00Å

R-factor:

0.189

R-free:

0.226

Authors:

K.Persson,H.D.Ly,M.Diekelmann,W.W.Wakarchuk,S.G.Withers, N.C.J.Strynadka

Key ref:

K.Persson et al. (2001). Crystal structure of the retaining galactosyltransferase LgtC from Neisseria meningitidis in complex with donor and acceptor sugar analogs.. Nat Struct Biol, 8, 166-175. [PubMed id: 11175908] [DOI: 10.1038/84168]

Date:

29-Nov-00

Release date:

14-Feb-01

Related entries:

1g9r
1g9r contains the same protein in complex with the donor
sugar analog.

Quick_links

Procheck

Clefts

Surface

Key reference

DOI no: 10.1038/84168

Nat Struct Biol 8:166-175 (2001)

PubMed id: 11175908

Crystal structure of the retaining galactosyltransferase LgtC from Neisseria meningitidis in complex with donor and acceptor sugar analogs.

K.Persson, H.D.Ly, M.Dieckelmann, W.W.Wakarchuk, S.G.Withers, N.C.Strynadka.

ABSTRACT

Many bacterial pathogens express lipooligosaccharides that mimic human cell surface glycoconjugates, enabling them to attach to host receptors and to evade the immune response. In Neisseria meningitidis, the galactosyltransferase LgtC catalyzes a key step in the biosynthesis of lipooligosaccharide structure by transferring alpha-d-galactose from UDP-galactose to a terminal lactose. The product retains the configuration of the donor sugar glycosidic bond; LgtC is thus a retaining glycosyltranferase. We report the 2 A crystal structures of the complex of LgtC with manganese and UDP 2-deoxy-2-fluoro-galactose (a donor sugar analog) in the presence and absence of the acceptor sugar analog 4'-deoxylactose. The structures, together with results from site-directed mutagenesis and kinetic analysis, give valuable insights into the unique catalytic mechanism and, as the first structure of a glycosyltransferase in complex with both the donor and acceptor sugars, provide a starting point for inhibitor design.

Selected figure(s)

Figure 1.
Figure 1. Glycosyl transfer reactions. a, The LgtC catalyzed transfer of galactose from UDP-Gal to the LPS core oligosaccharide of Neisseria. b, Proposed catalytic mechanism of inverting -galactosyltransferases. c, Proposed catalytic mechanism of retaining -galactosyltransferases.

Figure 4.
Figure 4. The active site. a, The donor sugar UDP-Gal and the acceptor sugar lactose are shown, in stereo, as ball-and-stick models (with red and green sticks, respectively) in a refined 2F[o] - F[c] map contoured at 1.2 . Amino acids interacting with the substrates are labeled. The loops that fold over the active site (residues 75 -80 and 246 -251) are colored green. b, Molecular surface representation of the active site. UDP-Gal and 4'-deoxylactose are shown in ball-and-stick form. UDP-Gal is almost completely buried in the enzyme while 4'-deoxylactose is bound in an open pocket that is more accessible to solvent. c, Stereo view of the hydrogen bonding network of Gln 189 and the distance and angle to the anomeric carbon C1'. Distances are in Å.

The above figures are reprinted by permission from Macmillan Publishers Ltd: Nat Struct Biol (2001, 8, 166-175) copyright 2001.

Figures were selected by an automated process.