Dataset Information

The role of the conserved phenylalanine in the sigma54-interacting GAFTGA motif of bacterial enhancer binding proteins.

ABSTRACT: sigma(54)-dependent transcription requires activation by bacterial enhancer binding proteins (bEBPs). bEBPs are members of the AAA+ (ATPases associated with various cellular activities) protein family and typically form hexameric structures that are crucial for their ATPase activity. The precise mechanism by which the energy derived from ATP hydrolysis is coupled to biological output has several unknowns. Here we use Escherichia coli PspF, a model bEBP involved in the transcription of stress response genes (psp operon), to study determinants of its contact features with the closed promoter complex. We demonstrate that substitution of a highly conserved phenylalanine (F85) residue within the L1 loop GAFTGA motif affects (i) the ATP hydrolysis rate of PspF, demonstrating the link between L1 and the nucleotide binding pocket; (ii) the internal organization of the hexameric ring; and (iii) sigma(54) interactions. Importantly, we provide evidence for a close relationship between F85 and the -12 DNA fork junction structure, which may contribute to key interactions during the energy coupling step and the subsequent remodelling of the Esigma(54) closed complex. The functionality of F85 is distinct from that of other GAFTGA residues, especially T86 where in contrast to F85 a clean uncoupling phenotype is observed.

SUBMITTER: Zhang N

PROVIDER: S-EPMC2764435 | biostudies-literature | 2009 Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

The role of the conserved phenylalanine in the sigma54-interacting GAFTGA motif of bacterial enhancer binding proteins.

Zhang Nan N Joly Nicolas N Burrows Patricia C PC Jovanovic Milija M Wigneshweraraj Siva R SR Buck Martin M

Nucleic acids research 20090819 18

sigma(54)-dependent transcription requires activation by bacterial enhancer binding proteins (bEBPs). bEBPs are members of the AAA+ (ATPases associated with various cellular activities) protein family and typically form hexameric structures that are crucial for their ATPase activity. The precise mechanism by which the energy derived from ATP hydrolysis is coupled to biological output has several unknowns. Here we use Escherichia coli PspF, a model bEBP involved in the transcription of stress res ...[more]

PMID: 19692583

Similar Datasets

Project description:Cell-autonomous immunity relies on the rapid detection of invasive pathogens by host proteins. Guanylate binding proteins (GBPs) have emerged as key mediators of vertebrate immune defense through their ability to recognize a diverse array of intracellular pathogens and pathogen-containing cellular compartments. Human and mouse GBPs have been shown to target distinct groups of microbes, although the molecular determinants of pathogen specificity remain unclear. We show that rapid diversification of a C-terminal polybasic motif (PBM) in primate GBPs controls recognition of the model cytosolic bacterial pathogen Shigella flexneri By swapping this membrane-binding motif between primate GBP orthologs, we found that the ability to target S. flexneri has been enhanced and lost in specific lineages of New World primates. Single substitutions in rapidly evolving sites of the GBP1 PBM are sufficient to abolish or restore bacterial detection abilities, illustrating a role for epistasis in the evolution of pathogen recognition. We further demonstrate that the squirrel monkey GBP2 C-terminal domain recently gained the ability to target S. flexneri through a stepwise process of convergent evolution. These findings reveal a mechanism by which accelerated evolution of a PBM shifts GBP target specificity and aid in resolving the molecular basis of GBP function in cell-autonomous immune defense.IMPORTANCE Many infectious diseases are caused by microbes that enter and survive within host cells. Guanylate binding proteins (GBPs) are a group of immune proteins which recognize and inhibit a variety of intracellular pathogenic microbes. We discovered that a short sequence within GBPs required for the detection of bacteria, the polybasic motif (PBM), has been rapidly evolving between primate species. By swapping PBMs between primate GBP1 genes, we were able to show that specific sequences can both reduce and improve the ability of GBP1 to target intracellular bacteria. We also show that the ability to envelop bacteria has independently evolved in GBP2 of South American monkeys. Taking the results together, this report illustrates how primate GBPs have adapted to defend against infectious pathogens.

Dataset Information

The role of the conserved phenylalanine in the sigma54-interacting GAFTGA motif of bacterial enhancer binding proteins.

Publications

The role of the conserved phenylalanine in the sigma54-interacting GAFTGA motif of bacterial enhancer binding proteins.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure