Linked Life Data

10387028

Source:http://linkedlifedata.com/resource/pubmed/id/10387028

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
24
pubmed:dateCreated
1999-7-15
pubmed:abstractText
The formal equilibrium reduction potentials of recombinant electron transport protein, rubredoxin (MW = 7500 Da), from both the mesophilic Clostridium pasteurianum (Topt = 37 degrees C) and hyperthermophilic Pyrococcus furiosus (Topt = 95 degrees C) were recorded as a function of pressure and temperature. Measurements were made utilizing a specially designed stainless steel electrochemical cell that easily maintains pressures between 1 and 600 atm and a temperature-controlled cell that maintains temperatures between 4 and 100 degrees C. The reduction potential of P. furiosus rubredoxin was determined to be 31 mV at 25 degrees C and 1 atm, -93 mV at 95 degrees C and 1 atm, and 44 mV at 25 degrees C and 400 atm. Thus, the reduction potential of P. furiosus rubredoxin obtained under standard conditions is likely to be dramatically different from the reduction potential obtained under its normal operating conditions. Thermodynamic parameters associated with electron transfer were determined for both rubredoxins (for C. pasteurianum, DeltaV degrees = -27 mL/mol, DeltaS degrees = -36 cal K-1 mol-1, and DeltaH degrees = -10 kcal/mol, and for P. furiosus, DeltaV degrees = -31 mL/mol, DeltaS degrees = -41 cal K-1 mol-1, and DeltaH degrees = -13 kcal/mol) from its pressure- and temperature-reduction potential profiles. The thermodynamic parameters for electron transfer (DeltaV degrees, DeltaS degrees, and DeltaH degrees ) for both proteins were very similar, which is not surprising considering their structural similarities and sequence homology. Despite the fact that these two proteins exhibit dramatic differences in thermostability, it appears that structural changes that confer dramatic differences in thermostability do not significantly alter electron transfer reactivity. The experimental changes in reduction potential as a function of pressure and temperature were simulated using a continuum dielectric electrostatic model (DELPHI). A reasonable estimate of the protein dielectric constant (epsilonprotein) of 6 for both rubredoxins was determined from these simulations. A discussion is presented regarding the analysis of electrostatic interaction energies of biomolecules through pressure- and temperature-controlled electrochemical studies.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
38
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
7874-80
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
Redox properties of mesophilic and hyperthermophilic rubredoxins as a function of pressure and temperature.
pubmed:affiliation
Department of Chemistry, Florida Institute of Technology, Melbourne 32901-6988, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.