PMID- 26637603
OWN - NLM
STAT- MEDLINE
DCOM- 20161024
LR  - 20181113
IS  - 1098-5336 (Electronic)
IS  - 0099-2240 (Print)
IS  - 0099-2240 (Linking)
VI  - 82
IP  - 4
DP  - 2016 Feb 15
TI  - Involvement of Agrobacterium tumefaciens Galacturonate Tripartite ATP-Independent 
      Periplasmic (TRAP) Transporter GaaPQM in Virulence Gene Expression.
PG  - 1136-1146
LID - 10.1128/AEM.02891-15 [doi]
AB  - Monosaccharides capable of serving as nutrients for the soil bacterium 
      Agrobacterium tumefaciens are also inducers of the vir regulon present in the 
      tumor-inducing (Ti) plasmid of this plant pathogen. One such monosaccharide is 
      galacturonate, the predominant monomer of pectin found in plant cell walls. This 
      ligand is recognized by the periplasmic sugar binding protein ChvE, which 
      interacts with the VirA histidine kinase that controls vir gene expression. 
      Although ChvE is also a member of the ChvE-MmsAB ABC transporter involved in the 
      utilization of many neutral sugars, it is not involved in galacturonate 
      utilization. In this study, a putative tripartite ATP-independent periplasmic 
      (TRAP) transporter, GaaPQM, is shown to be essential for the utilization of 
      galacturonic acid; we show that residue R169 in the predicted sugar binding site 
      of the GaaP is required for activity. The gene upstream of gaaPQM (gaaR) encodes 
      a member of the GntR family of regulators. GaaR is shown to repress the 
      expression of gaaPQM, and the repression is relieved in the presence of the 
      substrate for GaaPQM. Moreover, GaaR is shown to bind putative promoter regions 
      in the sequences required for galacturonic acid utilization. Finally, A. 
      tumefaciens strains carrying a deletion of gaaPQM are more sensitive to 
      galacturonate as an inducer of vir gene expression, while the overexpression of 
      gaaPQM results in strains being less sensitive to this vir inducer. This supports 
      a model in which transporter activity is crucial in ensuring that vir gene 
      expression occurs only at sites of high ligand concentration, such as those at a 
      plant wound site.
CI  - Copyright (c) 2016, American Society for Microbiology. All Rights Reserved.
FAU - Zhao, Jinlei
AU  - Zhao J
AD  - Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, 
      USA.
FAU - Binns, Andrew N
AU  - Binns AN
AD  - Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, 
      USA abinns@sas.upenn.edu.
LA  - eng
SI  - PDB/4N8Y
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, Non-P.H.S.
DEP - 20151204
PL  - United States
TA  - Appl Environ Microbiol
JT  - Applied and environmental microbiology
JID - 7605801
RN  - 0 (Hexuronic Acids)
RN  - 0 (Periplasmic Proteins)
RN  - 0 (Repressor Proteins)
RN  - 0 (Virulence Factors)
RN  - 4JK6RN80GF (galacturonic acid)
SB  - IM
MH  - Agrobacterium tumefaciens/genetics/*metabolism
MH  - DNA Mutational Analysis
MH  - Gene Deletion
MH  - *Gene Expression
MH  - Gene Expression Regulation, Bacterial
MH  - Hexuronic Acids/*metabolism
MH  - Periplasmic Proteins/genetics/*metabolism
MH  - Repressor Proteins/genetics/metabolism
MH  - Virulence Factors/*metabolism
PMC - PMC4751846
EDAT- 2015/12/08 06:00
MHDA- 2016/10/25 06:00
PMCR- 2016/08/05
CRDT- 2015/12/06 06:00
PHST- 2015/09/04 00:00 [received]
PHST- 2015/12/01 00:00 [accepted]
PHST- 2015/12/06 06:00 [entrez]
PHST- 2015/12/08 06:00 [pubmed]
PHST- 2016/10/25 06:00 [medline]
PHST- 2016/08/05 00:00 [pmc-release]
AID - AEM.02891-15 [pii]
AID - 02891-15 [pii]
AID - 10.1128/AEM.02891-15 [doi]
PST - epublish
SO  - Appl Environ Microbiol. 2015 Dec 4;82(4):1136-1146. doi: 10.1128/AEM.02891-15. 
      Print 2016 Feb 15.