3rub
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CRYSTAL STRUCTURE OF THE UNACTIVATED FORM OF RIBULOSE-1,5-BISPHOSPHATE CARBOXYLASE(SLASH)OXYGENASE FROM TOBACCO REFINED AT 2.0-ANGSTROMS RESOLUTION
OverviewOverview
The structure of the unactivated form of ribulose-1,5-bisphosphate, carboxylase/oxygenase was refined at a resolution of 2.0 A to an R-factor, of 17.1%. The previous model (Chapman et al., 1988) was extensively, rebuilt, and the small subunit was retraced. The refined model consists of, residues 22-63 and 69-467 of the large subunit and the complete small, subunit. A striking feature of the model is that several loops have very, high B-factors, probably representing mobile regions of the molecule. An, examination of the intersubunit contacts shows that the L8S8 hexadecamer, is composed of four L2 dimers. The dominant contacts between these L2, dimers are formed by the small subunits. This suggests that the small, subunits may be essential for maintaining the integrity of the L8S8, structure. The active site shows differences between the unactivated form, and the quaternary complex. In particular, Lys334 has moved out of the, active site by about 10A. This residue lies on loop 6 of the alpha beta, barrel, which is a particularly mobile loop. The site of, ribulose-1,5-bisphosphate carboxylase/oxygenase activation is well ordered, in the absence of the carbamylation of Lys201 and Mg2+ binding. The, residues are held poised by a network of hydrogen bonds. In the, unactivated state, the active site is accessible to substrate binding.
About this StructureAbout this Structure
3RUB is a Protein complex structure of sequences from [1] with SO4 and ASN as ligands. Active as Ribulose-bisphosphate carboxylase, with EC number 4.1.1.39 Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of the unactivated form of ribulose-1,5-bisphosphate carboxylase/oxygenase from tobacco refined at 2.0-A resolution., Curmi PM, Cascio D, Sweet RM, Eisenberg D, Schreuder H, J Biol Chem. 1992 Aug 25;267(24):16980-9. PMID:1512238
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