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Title: Serine 363 of a hydrophobic region of Archaeal ribulose 1,5-bisphosphate carboxylase/oxygenase from Archaeoglobus fulgidus and Thermococcus kodakaraensis affects CO2/O2 substrate specificity and oxygen sensitivity

Archaeal ribulose 1, 5-bisphospate carboxylase/oxygenase (RubisCO) is differentiated from other RubisCO enzymes and is classified as a form III enzyme, as opposed to the form I and form II RubisCOs typical of chemoautotrophic bacteria and prokaryotic and eukaryotic phototrophs. The form III enzyme from archaea is particularly interesting as several of these proteins exhibit unusual and reversible sensitivity to molecular oxygen, including the enzyme from Archaeoglobus fulgidus. Previous studies with A. fulgidus RbcL2 had shown the importance of Met-295 in oxygen sensitivity and pointed towards the potential significance of another residue (Ser-363) found in a hydrophobic pocket that is conserved in all RubisCO proteins. In the current study, further structure/function studies have been performed focusing on Ser-363 of A. fulgidus RbcL2; various changes in this and other residues of the hydrophobic pocket point to and definitively establish the importance of Ser-363 with respect to interactions with oxygen. In addition, previous findings had indicated discrepant CO2/O2 specificity determinations of the Thermococcus kodakaraensis RubisCO, a close homolog of A. fulgidus RbcL2. As a result, it is shown here that the T. kodakaraensis enzyme exhibits a similar substrate specificity as the A. fulgidus enzyme and is also oxygen sensitive, with equivalent residues involvedmore » in oxygen interactions.« less
Authors:
 [1] ;  [1] ;  [2]
  1. The Ohio State Univ., Columbus, OH (United States)
  2. Univ. of Freiburg (Germany)
Publication Date:
OSTI Identifier:
1324973
Grant/Contract Number:
FG02-08ER15976
Type:
Accepted Manuscript
Journal Name:
PLoS ONE
Additional Journal Information:
Journal Volume: 10; Journal Issue: 9; Journal ID: ISSN 1932-6203
Publisher:
Public Library of Science
Research Org:
The Ohio State Univ., Columbus, OH (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES Ribulose-1,5-bisphosphate carboxylase oxygenase; oxygen; enzymes; complement system; enzyme structure; crystal structure; enzyme assays; recombinant proteins