1uzd

Chlamydomonas,Spinach Chimeric Rubisco

spinqualitylabelsall models 1uzd, resolution 2.40Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1uzd is a 16 chain structure with sequence from Chlamydomonas reinhardtii and Spinacia oleracea. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.4Å Ligands: CAP, EDO, HYP, KCX, MG, SMC Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function RBL_CHLRE RuBisCO catalyzes two reactions: the carboxylation of D-ribulose 1,5-bisphosphate, the primary event in carbon dioxide fixation, as well as the oxidative fragmentation of the pentose substrate in the photorespiration process. Both reactions occur simultaneously and in competition at the same active site.[HAMAP-Rule:MF_01338] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Comparison of subunit sequences and X-ray crystal structures of ribulose-1,5-bisphosphate carboxylase/oxygenase indicates that the loop between beta-strands A and B of the small subunit is one of the most variable regions of the holoenzyme. In prokaryotes and nongreen algae, the loop contains 10 residues. In land plants and green algae, the loop is comprised of approximately 22 and 28 residues, respectively. Previous studies indicated that the longer betaA-betaB loop was required for the assembly of cyanobacterial small subunits with plant large subunits in isolated chloroplasts. In the present study, chimeric small subunits were constructed by replacing the loop of the green alga Chlamydomonas reinhardtii with the sequences of Synechococcus or spinach. When these engineered genes were transformed into a Chlamydomonas mutant that lacks small-subunit genes, photosynthesis-competent colonies were recovered, indicating that loop size is not essential for holoenzyme assembly. Whereas the Synechococcus loop causes decreases in carboxylation V(max), K(m)(O(2)), and CO(2)/O(2) specificity, the spinach loop causes complementary decreases in carboxylation V(max), K(m)(O(2)), and K(m)(CO(2)) without a change in specificity. X-ray crystal structures of the engineered proteins reveal remarkable similarity between the introduced betaA-betaB loops and the respective loops in the Synechococcus and spinach enzymes. The side chains of several large-subunit residues are altered in regions previously shown by directed mutagenesis to influence CO(2)/O(2) specificity. Differences in the catalytic properties of divergent Rubisco enzymes may arise from differences in the small-subunit betaA-betaB loop. This loop may be a worthwhile target for genetic engineering aimed at improving photosynthetic CO(2) fixation. Chimeric small subunits influence catalysis without causing global conformational changes in the crystal structure of ribulose-1,5-bisphosphate carboxylase/oxygenase.,Karkehabadi S, Peddi SR, Anwaruzzaman M, Taylor TC, Cederlund A, Genkov T, Andersson I, Spreitzer RJ Biochemistry. 2005 Jul 26;44(29):9851-61. PMID:16026157 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also RuBisCO 3D structures

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