Linked Life Data

2831054

Source:http://linkedlifedata.com/resource/pubmed/id/2831054

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1988-4-11
pubmed:abstractText
The cytoplasmic membrane of the methanogenic archaebacterium Methanobacterium thermoautotrophicum does not contain cytochromes, but did contain a corrinoid protein of molecular mass about 33 kDa which, after treatment with 10 mg Triton X-100/mg protein, was contained in a protein complex of about 500 kDa. Washed membranes from 1 g dry cells contained about 70 nmol of the cobamide factor III (5-hydroxybenzimidazolyl cobamide) as the sole corrinoid. The corrinoid-containing protein complex was purified and some of its properties were studied. According to several criteria it is an integral membrane protein complex. The corrinoid-protein complex, after about 100-fold purification, gave a single band on native PAGE and still had molecular mass of about 500 kDa. In SDS-PAGE several subunits were observed: in addition to the corrinoid-carrying subunit of about 33 kDa, other polypeptides of approximately 28 kDa, 26 kDa, and possibly 23 kDa were present. One mole of the purified 500-kDa protein complex contained greater than or equal to eight moles of the cobamide factor III. It was estimated that the corrinoid-protein complex accounts for 8% of the membrane protein of M. thermoautotrophicum. The visible spectrum of the oxidized protein exhibited absorbance maxima at 547 nm, 511 nm, and a shoulder at 468 nm, which disappeared upon reduction with dithionite. The midpoint potential of this transition was around -145 mV (pH 7). With EPR a Co2+ signal was observed within -50 mV and -350 mV with a maximum around -200 mV. Possible reasons for the disappearance of the Co2+ signal at low redox potentials are discussed. The line shape of the Co2+ signal was similar to that of Co2+ in free corrinoids. The signal of Co2+ could also be evoked by reduction with 5 mM dithiothreitol. From the redox properties of the corrinoid membrane protein it may be expected that in vivo the cobalt may become reduced and reoxidized. Its possible function as an electron-mediating membrane protein in the metabolism of methanogenic bacteria is discussed.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0014-2956
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
171
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
589-97
pubmed:dateRevised
2007-7-23
pubmed:meshHeading
pubmed:year
1988
pubmed:articleTitle
Purification and some properties of the corrinoid-containing membrane protein from Methanobacterium thermoautotrophicum.
pubmed:affiliation
Abteilung Angewandte Mikrobiologie, Universität Ulm, Federal Republic of Germany.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't