Burkholderia cenocepacia and Salmonella enterica ArnT proteins that transfer 4-amino-4-deoxy-L-arabinose to lipopolysaccharide share membrane topology and functional amino acids


Autoria(s): Tavares-Carreón, Faviola; Patel, Kinnari B.; Valvano, Miguel A.
Data(s)

01/06/2015

Resumo

We recently demonstrated that incorporation of 4-amino-4-deoxy-l-arabinose (l-Ara4N) to the lipid A moiety of lipopolysaccharide (LPS) is required for transport of LPS to the outer membrane and viability of the Gram-negative bacterium Burkholderia cenocepacia. ArnT is a membrane protein catalyzing the transfer of l-Ara4N to the LPS molecule at the periplasmic face of the inner membrane, but its topology and mechanism of action are not well characterized. Here, we elucidate the topology of ArnT and identify key amino acids that likely contribute to its enzymatic function. PEGylation assays using a cysteineless version of ArnT support a model of 13 transmembrane helices and a large C-terminal region exposed to the periplasm. The same topological configuration is proposed for the Salmonella enterica serovar Typhimurium ArnT. Four highly conserved periplasmic residues in B. cenocepacia ArnT, tyrosine-43, lysine-69, arginine-254 and glutamic acid-493, were required for activity. Tyrosine-43 and lysine-69 span two highly conserved motifs, 42RYA44 and 66YFEKP70, that are found in ArnT homologues from other species. The same residues in S. enterica ArnT are also needed for function. We propose these aromatic and charged amino acids participate in either undecaprenyl phosphate-l-Ara4N substrate recognition or transfer of l-Ara4N to the LPS.

Formato

application/pdf

Identificador

http://pure.qub.ac.uk/portal/en/publications/burkholderia-cenocepacia-and-salmonella-enterica-arnt-proteins-that-transfer-4amino4deoxylarabinose-to-lipopolysaccharide-share-membrane-topology-and-functional-amino-acids(822a78a0-c8f9-40e7-866d-57ae118d5479).html

http://dx.doi.org/10.1038/srep10773

http://pure.qub.ac.uk/ws/files/15852222/srep10773.pdf

Idioma(s)

eng

Direitos

info:eu-repo/semantics/openAccess

Fonte

Tavares-Carreón , F , Patel , K B & Valvano , M A 2015 , ' Burkholderia cenocepacia and Salmonella enterica ArnT proteins that transfer 4-amino-4-deoxy-L-arabinose to lipopolysaccharide share membrane topology and functional amino acids ' Scientific Reports , vol 5 , 10773 . DOI: 10.1038/srep10773

Palavras-Chave #membrane protein #LIPOPOLYSACCHARIDE BIOSYNTHESIS #lipid A #polymyxin resistance #aminoarabinose
Tipo

article