Premium
l ‐Rhamnose catabolism in archaea
Author(s) -
Reinhardt Andreas,
Johnsen Ulrike,
Schönheit Peter
Publication year - 2019
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.14213
Subject(s) - haloferax volcanii , sulfolobus solfataricus , crenarchaeota , biology , biochemistry , rhamnose , catabolism , archaea , gene cluster , dehydratase , hydrolase , dehydrogenase , mutant , gene , enzyme , galactose
Summary The halophilic archaeon Haloferax volcanii utilizes l ‐rhamnose as a sole carbon and energy source. It is shown that l ‐rhamnose is taken up by an ABC transporter and is oxidatively degraded to pyruvate and l ‐lactate via the diketo‐hydrolase pathway. The genes involved in l ‐rhamnose uptake and degradation form a l ‐rhamnose catabolism ( rhc ) gene cluster. The rhc cluster also contains a gene, rhcR , that encodes the transcriptional regulator RhcR which was characterized as an activator of all rhc genes. 2‐keto‐3‐deoxy‐ l ‐rhamnonate, a metabolic intermediate of l ‐rhamnose degradation, was identified as inducer molecule of RhcR. The essential function of rhc genes for uptake and degradation of l ‐rhamnose was proven by the respective knockout mutants. Enzymes of the diketo‐hydrolase pathway, including l ‐rhamnose dehydrogenase, l ‐rhamnonolactonase, l ‐rhamnonate dehydratase, 2‐keto‐3‐deoxy‐ l ‐rhamnonate dehydrogenase and 2,4‐diketo‐3‐deoxy‐ l ‐rhamnonate hydrolase, were characterized. Further, genes of the diketo‐hydrolase pathway were also identified in the hyperthermophilic crenarchaeota Vulcanisaeta distributa and Sulfolobus solfataricus and selected enzymes were characterized, indicating the presence of the diketo‐hydrolase pathway in these archaea. Together, this is the first comprehensive description of l ‐rhamnose catabolism in the domain of archaea.