@article {1201, title = {Identification and Characterization of an Archaeal Kojibiose Catabolic Pathway in the Hyperthermophilic Pyrococcus sp. Strain ST04.}, journal = {J Bacteriol}, volume = {196}, year = {2014}, month = {2014 Mar}, pages = {1122-31}, abstract = {

A unique gene cluster responsible for kojibiose utilization was identified in the genome of Pyrococcus sp. strain ST04. The proteins it encodes hydrolyze kojibiose, a disaccharide product of glucose caramelization, and form glucose-6-phosphate (G6P) in two steps. Heterologous expression of the kojibiose-related enzymes in Escherichia coli revealed that two genes, Py04_1502 and Py04_1503, encode kojibiose phosphorylase (designated PsKP, for Pyrococcus sp. strain ST04 kojibiose phosphorylase) and β-phosphoglucomutase (PsPGM), respectively. Enzymatic assays show that PsKP hydrolyzes kojibiose to glucose and β-glucose-1-phosphate (β-G1P). The Km values for kojibiose and phosphate were determined to be 2.53 {\textpm} 0.21 mM and 1.34 {\textpm} 0.04 mM, respectively. PsPGM then converts β-G1P into G6P in the presence of 6 mM MgCl2. Conversion activity from β-G1P to G6P was 46.81 {\textpm} 3.66 U/mg, and reverse conversion activity from G6P to β-G1P was 3.51 {\textpm} 0.13 U/mg. The proteins are highly thermostable, with optimal temperatures of 90{\textdegree}C for PsKP and 95{\textdegree}C for PsPGM. These results indicate that Pyrococcus sp. strain ST04 converts kojibiose into G6P, a substrate of the glycolytic pathway. This is the first report of a disaccharide utilization pathway via phosphorolysis in hyperthermophilic archaea.

}, issn = {1098-5530}, doi = {10.1128/JB.01222-13}, author = {Jung, Jong-Hyun and Seo, Dong-Ho and Holden, James F and Park, Cheon-Seok} }