E-resources
-
Rosa, Leonardo T.; Dix, Samuel R.; Rafferty, John B.; Kelly, David J.
Journal of Molecular Biology/Journal of molecular biology, 01/2019, Volume: 431, Issue: 2Journal Article
C4-dicarboxylates play a central role in cellular physiology as key metabolic intermediates. Under aerobic conditions, they participate in the citric acid cycle, while in anaerobic bacteria, they are important in energy-conserving fermentation and respiration processes. Ten different families of secondary transporters have been described to participate in C4-dicarboxylate movement across biological membranes, but only one of these utilizes an extracytoplasmic solute binding protein to achieve high-affinity uptake. Here, we identify the MatBAC system from the photosynthetic bacterium Rhodopseudomonas palustris as the first member of the tripartite tricarboxylate transport family to be involved in C4-dicarboxylate transport. Tryptophan fluorescence spectroscopy showed that MatC, the periplasmic binding protein from this system, binds to l- and d-malate with Kd values of 27 and 21 nM, respectively, the highest reported affinity to date for these C4-dicarboxylates, and to succinate (Kd = 110 nM) and fumarate (Kd = 400 nM). The 2.1-Å crystal structure of MatC with bound malate shows a high level of substrate coordination, with participation of two water molecules that bridge hydrogen bonds between the ligand proximal carboxylic group and the main chain of two conserved loops in the protein structure. The substrate coordination in MatC correlates with the binding data and explains the protein's selectivity for different substrates and respective binding affinities. Our results reveal a new function in C4-dicarboxylate transport by members of the poorly characterized tripartite tricarboxylate transport family, which are widely distributed in bacterial genomes but for which details of structure–function relationships and transport mechanisms have been lacking. Display omitted •Only secondary transporters are known to move C4-dicarboxylates across biological membranes.•We identify MatBAC, a novel C4-dicarboxylate transporter with a periplasmic binding protein, MatC.•MatBAC is the first known tripartite tricarboxylate transporter for C4-dicarboxylates.•MatC binds to d- and l-malate with very high affinity and to succinate and fumarate.•A 2.1-Å crystal structure of MatC bound to malate shows participation of two conserved water molecules.
Shelf entry
Permalink
- URL:
Impact factor
Access to the JCR database is permitted only to users from Slovenia. Your current IP address is not on the list of IP addresses with access permission, and authentication with the relevant AAI accout is required.
Year | Impact factor | Edition | Category | Classification | ||||
---|---|---|---|---|---|---|---|---|
JCR | SNIP | JCR | SNIP | JCR | SNIP | JCR | SNIP |
Select the library membership card:
If the library membership card is not in the list,
add a new one.
DRS, in which the journal is indexed
Database name | Field | Year |
---|
Links to authors' personal bibliographies | Links to information on researchers in the SICRIS system |
---|
Source: Personal bibliographies
and: SICRIS
The material is available in full text. If you wish to order the material anyway, click the Continue button.