4KUN

Crystal structure of Legionella pneumophila Lpp1115 / KaiB

Summary for 4KUN

• Entry DOI: 10.2210/pdb4kun/pdb
• Descriptor: Hypothetical protein Lpp1115 (2 entities in total)
• Functional Keywords: midwest center for structural genomics, mcsg, psi-biology, alpha and beta proteins (a/b), thioredoxin fold, unknown function
• Biological source: Legionella pneumophila
• Total number of polymer chains: 2
• Total formula weight: 20337.52

Authors

Petit, P.,Stogios, P.J.,Stein, A.,Wawrzak, Z.,Skarina, T.,Daniels, C.,Di Leo, R.,Buchrieser, C.,Savchenko, A.,Joachimiak, A.,Midwest Center for Structural Genomics (MCSG) (deposition date: 2013-05-22, release date: 2013-06-05, Last modification date: 2024-11-20)

Primary citation

Loza-Correa, M.,Sahr, T.,Rolando, M.,Daniels, C.,Petit, P.,Skarina, T.,Gomez Valero, L.,Dervins-Ravault, D.,Honore, N.,Savchenko, A.,Buchrieser, C.
The Legionella pneumophila kai operon is implicated in stress response and confers fitness in competitive environments.
Environ Microbiol, 16:359-381, 2014

PubMed Abstract: Legionella pneumophila uses aquatic protozoa as replication niche and protection from harsh environments. Although L. pneumophila is not known to have a circadian clock, it encodes homologues of the KaiBC proteins of Cyanobacteria that regulate circadian gene expression. We show that L. pneumophila kaiB, kaiC and the downstream gene lpp1114, are transcribed as a unit under the control of the stress sigma factor RpoS. KaiC and KaiB of L. pneumophila do not interact as evidenced by yeast and bacterial two-hybrid analyses. Fusion of the C-terminal residues of cyanobacterial KaiB to Legionella KaiB restores their interaction. In contrast, KaiC of L. pneumophila conserved autophosphorylation activity, but KaiB does not trigger the dephosphorylation of KaiC like in Cyanobacteria. The crystal structure of L. pneumophila KaiB suggests that it is an oxidoreductase-like protein with a typical thioredoxin fold. Indeed, mutant analyses revealed that the kai operon-encoded proteins increase fitness of L. pneumophila in competitive environments, and confer higher resistance to oxidative and sodium stress. The phylogenetic analysis indicates that L. pneumophila KaiBC resemble Synechosystis KaiC2B2 and not circadian KaiB1C1. Thus, the L. pneumophila Kai proteins do not encode a circadian clock, but enhance stress resistance and adaption to changes in the environments.

PubMed: 23957615
DOI: 10.1111/1462-2920.12223

Experimental method

X-RAY DIFFRACTION (1.95 Å)