ISSN:
1432-1017
Keywords:
Small-angle X-ray scattering
;
solution structure
;
ribulose-1,5-bisphosphate
;
carboxylase/oxygenase
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Physics
Notes:
Abstract The quaternary structure of ribulose-1,5-bisphosphate carboxylase-oxygenase (rubisco) from Rhodospirillum rubrum, an enzyme consisting of two large subunits, L2, was investigated by small-angle X-ray scattering. In the presence of HCO 3 - and Mg2+, rubisco is in the active state and displays a radius of gyration of 2.96 nm, a maximum diameter of 9.5 nm and a volume of 170 nm3. A model is presented where the subunits are arranged back-to-back, rotated relative to each other by 90°, and shifted by 1.3 nm. Upon inactivation by removal of HCO 3 - and Mg2+, the model swells slightly without any distinct changes in configuration. This contrasts with our previous observations with rubisco from Alcaligenes eutrophus, an enzyme composed of small (S) and large (L) subunits, L8S8, where inactivation gives rise to substantial changes in configuration.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00263065
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