Cyclic-2,3-diphosphoglycerate cycle in methanogenic bacteria

Conference · Fri May 01 00:00:00 EDT 1987 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:6179733

Fahrney, D E; Harper, S H; Krueger, R D

A new and unprecedented model for P/sub i/ translocation into Methanobacterium thermoautotrophicum is proposed. It is based on an analysis of the rates of P/sub i/ uptake and concomitant flux through the cyclic-2,3-diphosphoglycerate (cDPG) pool in the presence of cyanide. CN/sup -/ completely blocks flow of carbon into cellular constituents, but methanogenesis continues at about 70%, indicating considerable energy flow. P/sub i/ uptake continued at 20% of control for 30 min or longer, resulting in an expansion of the intracellular P/sub i/ pool. During this period the flux of phosphate through the cDPG pool remained equal to the rate of P/sub i/ entry. The distribution of /sup 32/P in cDPG showed that the C-2 phosphoryl group was labeled preferentially, indicating that this phosphoryl group has a half-life under 10 min in the presence of CN/sup -/. Since CN/sup -/ completely blocks CO/sub 2/ fixation but does not interfere with cDPG turnover, cDPG is neither a biosynthetic intermediate nor a phosphate storage compound. Earlier they had demonstrated that this methanogen can transport P/sub i/ against a million-fold concentration gradient via a H/sub 2/-driven transport system having a K/sub m/ of 25 nM. The evidence that cDPG may play a role in this transport mechanism seems compelling, but further studies are needed.

• Research Organization: Colorado State Univ., Fort Collins
• OSTI ID: 6179733
• Report Number(s): CONF-870644-
• Journal Information: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Vol. 46:6; ISSN FEPRA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
BACTERIA
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL HALF-LIFE
BIOLOGICAL MODELS
CYANIDES
DAYS LIVING RADIOISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
MEMBRANE TRANSPORT
METHANOGENIC BACTERIA
MICROORGANISMS
NUCLEI
ODD-ODD NUCLEI
OXYGEN COMPOUNDS
PHOSPHATES
PHOSPHORUS 32
PHOSPHORUS COMPOUNDS
PHOSPHORUS ISOTOPES
RADIOISOTOPES
TRACER TECHNIQUES