Crystal Structure of Apo-GlmU from Mycobacterium tuberculosis

Experimental Data Snapshot

  • Resolution: 2.23 Å
  • R-Value Free: 0.271 
  • R-Value Work: 0.225 
  • R-Value Observed: 0.227 

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PknB-mediated phosphorylation of a novel substrate, N-acetylglucosamine-1-phosphate uridyltransferase, modulates its acetyltransferase activity.

Parikh, A.Verma, S.K.Khan, S.Prakash, B.Nandicoori, V.K.

(2009) J Mol Biol 386: 451-464

  • DOI: https://doi.org/10.1016/j.jmb.2008.12.031
  • Primary Citation of Related Structures:  
    3DJ4, 3DK5

  • PubMed Abstract: 

    Identifying direct targets of kinases and determining how their activities are regulated are central to understanding how they generate biological responses. Genetic and biochemical studies have shown that Mycobacterium tuberculosis serine/threonine protein kinases PknA and PknB play a role in modulating cell shape and possibly cell division. In this report, we show that the enzyme N-acetylglucosamine-1-phosphate uridyltransferase (GlmU) of M. tuberculosis is a novel substrate of PknB and is phosphorylated on threonine residues. GlmU carries out two important biochemical activities: a C-terminal domain catalyzes the transfer of acetyl group from acetyl coenzyme A to glucosamine-1-phosphate to produce N-acetylglucosamine-1-phosphate, which is converted into UDP-N-acetylglucosamine by the transfer of uridine 5'-monophosphate (from uridine 5'-triphosphate), a reaction catalyzed by the N-terminal domain. We determined the crystal structures of GlmU in apo form and UDP-N-acetylglucosamine-bound form, and analyzed them to identify threonine residues that may be accessible to PknB. The structure shows a two-domain architecture, with an N-terminal domain having an alpha/beta-like fold and with a C-terminal domain that forms a left-handed parallel beta-helix structure. Kinase assays with PknB using the N- and C-terminal domains of GlmU as substrates illustrated that PknB phosphorylates GlmU in the C-terminal domain. Furthermore, mutational studies reveal one of the five threonines present in region 414-439 to be phosphorylated by PknB. Structural and biochemical analyses have shown the significance of a variable C-terminal tail in regulating acetyltransferase activity. Notably, we demonstrate that although PknB-mediated phosphorylation of GlmU does not affect its uridyltransferase activity, it significantly modulates the acetyltransferase activity. These findings imply a role for PknB in regulating peptidoglycan synthesis by modulating the acetyltransferase activity of GlmU.

  • Organizational Affiliation

    National Institute of Immunology, New Delhi, India.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Bifunctional protein glmU495Mycobacterium tuberculosis H37RaMutation(s): 0 
Gene Names: glmUMRA_1026
EC: (PDB Primary Data), (PDB Primary Data)
Find proteins for P9WMN3 (Mycobacterium tuberculosis (strain ATCC 25618 / H37Rv))
Explore P9WMN3 
Go to UniProtKB:  P9WMN3
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP9WMN3
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.23 Å
  • R-Value Free: 0.271 
  • R-Value Work: 0.225 
  • R-Value Observed: 0.227 
  • Space Group: H 3
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 79.6α = 90
b = 79.6β = 90
c = 278γ = 120
Software Package:
Software NamePurpose
XSCALEdata scaling
PDB_EXTRACTdata extraction
MAR345dtbdata collection

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2009-05-19
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2024-03-20
    Changes: Data collection, Database references, Derived calculations