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Publication Abstract from PubMed

Cyclic di-GMP (c-di-GMP) is a ubiquitous bacterial second messenger that is involved in the regulation of cell surface-associated traits and the persistence of infections. Omnipresent GGDEF and EAL domains, which occur in various combinations with regulatory domains, catalyze c-di-GMP synthesis and degradation, respectively. The crystal structure of full-length YkuI from Bacillus subtilis, composed of an EAL domain and a C-terminal PAS-like domain, has been determined in its native form and in complex with c-di-GMP and Ca(2+). The EAL domain exhibits a triose-phosphate isomerase-barrel fold with one antiparallel beta-strand. The complex with c-di-GMP-Ca(2+) defines the active site of the putative phosphodiesterase located at the C-terminal end of the beta-barrel. The EAL motif is part of the active site with Glu-33 of the motif being involved in cation coordination. The structure of the complex allows the proposal of a phosphodiesterase mechanism, in which the divalent cation and the general base Glu-209 activate a catalytic water molecule for nucleophilic in-line attack on the phosphorus. The C-terminal domain closely resembles the PAS-fold. Its pocket-like structure could accommodate a yet unknown ligand. YkuI forms a tight dimer via EAL-EAL and trans EAL-PAS-like domain association. The possible regulatory significance of the EAL-EAL interface and a mechanism for signal transduction between sensory and catalytic domains of c-di-GMP-specific phosphodiesterases are discussed.

Crystal structures of YkuI and its complex with second messenger cyclic Di-GMP suggest catalytic mechanism of phosphodiester bond cleavage by EAL domains.,Minasov G, Padavattan S, Shuvalova L, Brunzelle JS, Miller DJ, Basle A, Massa C, Collart FR, Schirmer T, Anderson WF J Biol Chem. 2009 May 8;284(19):13174-84. Epub 2009 Feb 24. PMID:19244251^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.