6uew
From Proteopedia
Rubisco / CsoS2 N-peptide complex responsible for alpha-carboxysome cargo loading
Structural highlights
Function[RBL1_HALNC] 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. Both reactions occur simultaneously and in competition at the same active site.[HAMAP-Rule:MF_01338] [RBS_HALNC] 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. Both reactions occur simultaneously and in competition at the same active site. Publication Abstract from PubMedCarboxysomes are bacterial microcompartments that function as the centerpiece of the bacterial CO2-concentrating mechanism by facilitating high CO2 concentrations near the carboxylase Rubisco. The carboxysome self-assembles from thousands of individual proteins into icosahedral-like particles with a dense enzyme cargo encapsulated within a proteinaceous shell. In the case of the alpha-carboxysome, there is little molecular insight into protein-protein interactions that drive the assembly process. Here, studies on the alpha-carboxysome from Halothiobacillus neapolitanus demonstrate that Rubisco interacts with the N terminus of CsoS2, a multivalent, intrinsically disordered protein. X-ray structural analysis of the CsoS2 interaction motif bound to Rubisco reveals a series of conserved electrostatic interactions that are only made with properly assembled hexadecameric Rubisco. Although biophysical measurements indicate that this single interaction is weak, its implicit multivalency induces high-affinity binding through avidity. Taken together, our results indicate that CsoS2 acts as an interaction hub to condense Rubisco and enable efficient alpha-carboxysome formation. Multivalent interactions between CsoS2 and Rubisco mediate alpha-carboxysome formation.,Oltrogge LM, Chaijarasphong T, Chen AW, Bolin ER, Marqusee S, Savage DF Nat Struct Mol Biol. 2020 Mar;27(3):281-287. doi: 10.1038/s41594-020-0387-7. Epub, 2020 Mar 2. PMID:32123388[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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