Active site of ribulosebisphosphate carboxylase/oxygenase
Previous affinity labeling studies and comparative sequence analyses have identified two different lysines at the active site of ribulosebisphosphate carboxylase/oxygenase and have suggested their essentiality to function. The essential lysines occupy positions 166 and 329 in the Rhodospirillum rubrum enzyme and positions 175 and 334 in the spinach enzyme. Based on the pH-dependencies of inactivations of the two enzymes by trinitrobenzene sulfonate, Lys-166 (R. rubrum enzyme) exhibits a pK/sub a/ of 7.9 and Lys-334 (spinach enzyme) exhibits a pK/sub a/ of 9.0. These low pK/sub a/ values as well as the enhanced nucleophilicities of the lysyl residues argue that both are important to catalysis rather than to substrate binding. Lys-166 may correspond to the essential base that initiates catalysis and that displays a pK/sub a/ of 7.5 in the pH-curve for V/sub max//K/sub m/. Cross-linking experiments with 4,4'-diisothiocyano-2,2'-disulfonate stilbene demonstrate that the two active-site lysines are within 12 A. 50 refs., 7 figs., 1 tab.
- Research Organization:
- Oak Ridge National Lab., TN (USA); Tennessee Univ., Oak Ridge (USA). Graduate School of Biomedical Sciences
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 6381611
- Report Number(s):
- CONF-851254-1; ON: DE86004801
- Resource Relation:
- Conference: Conference on ribulose bisphosphate carboxylase-oxygenase, London, England, 4 Dec 1985
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
14 SOLAR ENERGY
RIBULOSE DIPHOSPHATE CARBOXYLASE
AMINO ACID SEQUENCE
BIOCHEMICAL REACTION KINETICS
MOLECULAR STRUCTURE
SPECIES DIVERSITY
EXPERIMENTAL DATA
GEL PERMEATION CHROMATOGRAPHY
LIQUID COLUMN CHROMATOGRAPHY
LYSINE
PEPTIDES
PH VALUE
RHODOSPIRILLUM
SPINACH
AMINO ACIDS
BACTERIA
CARBON-CARBON LYASES
CARBOXY-LYASES
CARBOXYLIC ACIDS
CHROMATOGRAPHY
DATA
ENZYMES
FOOD
INFORMATION
KINETICS
LYASES
MICROORGANISMS
NUMERICAL DATA
ORGANIC ACIDS
ORGANIC COMPOUNDS
PLANTS
PROTEINS
REACTION KINETICS
SEPARATION PROCESSES
VEGETABLES
550200* - Biochemistry
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Photobiological
& Thermochemical Conversion- (1980-)