Catalytic roles of flexible regions at the active site of ribulose-bisphosphate carboxylase/oxygenase (Rubisco)
Conference
·
OSTI ID:205848
Chemical and mutagenesis studies of Rubisco have identified Lys329 and Glu48 as active-site residues that are located in distinct, interacting domains from adjacent subunits. Crystallographic analyses have shown that Lys329 is the apical residue in a 12-residue flexible loop (loop 6) of the {Beta},{alpha}-barrel domain of the active site and that Glu48 resides at the end of helix B of the N-terminal domain of the active site. When phosphorylated ligands are bound by the enzyme, loop 6 adopts a closed conformation and, in concert with repositioning of helix B, thereby occludes the active site from the external environment. In this closed conformation, the {gamma}-carboxylate of Glu48 and the {epsilon}-amino group of Lys329 engage in intersubunit electrostatic interaction. By use of appropriate site-directed mutants of Rhodospirillum rubrum Rubisco, we are addressing several issues: the catalytic roles of Lys329 and Glu48, the functional significance of the intersubunit salt bridge comprised of these two residues, and the roles of loop 6 and helix B in stabilizing labile reaction intermediates. Characterization of novel products derived from misprocessing of D-ribulose-1,5-bisphosphate (RuBP) by the mutant proteins have illuminated the structure of the key intermediate in the normal oxygenase pathway.
- Research Organization:
- Oak Ridge National Lab., TN (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 205848
- Report Number(s):
- CONF-9508202--1; ON: DE96004399
- Country of Publication:
- United States
- Language:
- English
Similar Records
Function of active-site residues of ribulose-bisphosphate carboxylase/oxygenase (Rubisco)
The nature and alternate rates of the ribulose 1,5-bisphosphate (RuBP) carboxylase/oxygenase (Rubisco) oxygenation intermediate
The active site of ribulose-bisphosphate carboxylase/oxygenase
Conference
·
Sat Dec 31 23:00:00 EST 1988
·
OSTI ID:5729064
The nature and alternate rates of the ribulose 1,5-bisphosphate (RuBP) carboxylase/oxygenase (Rubisco) oxygenation intermediate
Conference
·
Sat Dec 30 23:00:00 EST 1995
·
OSTI ID:221924
The active site of ribulose-bisphosphate carboxylase/oxygenase
Conference
·
Mon Dec 31 23:00:00 EST 1990
·
OSTI ID:6074751