1geh
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CRYSTAL STRUCTURE OF ARCHAEAL RUBISCO (RIBULOSE 1,5-BISPHOSPHATE CARBOXYLASE/OXYGENASE)
OverviewOverview
BACKGROUND: Ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) is, the key enzyme of the Calvin-Benson cycle and catalyzes the primary, reaction of CO2 fixation in plants, algae, and bacteria. Rubiscos have, been so far classified into two types. Type I is composed of eight large, subunits (L subunits) and eight small subunits (S subunits) with, tetragonal symmetry (L8S8), but type II is usually composed only of two L, subunits (L2). Recently, some genuinely active Rubiscos of unknown, physiological function have been reported from archaea. RESULTS: The, crystal structure of Rubisco from the hyperthermophilic archaeon, Thermococcus kodakaraensis KOD1 (Tk-Rubisco) was determined at 2.8 A, resolution. The enzyme is composed only of L subunits and showed a novel, (L2)5 decameric structure. Compared to previously known type I enzymes, each L2 dimer is inclined approximately 16 degrees to form a toroid-shaped, decamer with its unique L2-L2 interfaces. Differential scanning, calorimetry (DSC), circular dichroism (CD), and gel permeation, chromatography (GPC) showed that Tk-Rubisco maintains its secondary, structure and decameric assembly even at high temperatures. CONCLUSIONS:, The present study provides the first structure of an archaeal Rubisco, an, unprecedented (L2)5 decamer. Biochemical studies indicate that Tk-Rubisco, maintains its decameric structure at high temperatures. The structure is, distinct from type I and type II Rubiscos and strongly supports that, Tk-Rubisco should be classified as a novel type III Rubisco.
About this StructureAbout this Structure
1GEH is a Single protein structure of sequence from Thermococcus kodakarensis with SO4 as ligand. Active as Ribulose-bisphosphate carboxylase, with EC number 4.1.1.39 Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of a novel-type archaeal rubisco with pentagonal symmetry., Kitano K, Maeda N, Fukui T, Atomi H, Imanaka T, Miki K, Structure. 2001 Jun;9(6):473-81. PMID:11435112
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