|
type |
Journal Article |
authors |
Engelhardt, H.; Forchhammer, K.; Muller, S.; Goldie, K. N.; Bock, A. |
title |
Structure of selenocysteine synthase from Escherichia coli and location of tRNA in the seryl-tRNA(sec)-enzyme complex |
journal |
Mol Microbiol |
Activity |
2.9.1.1 |
ui |
93116584 |
year |
(1992) |
volume |
6 |
number |
23 |
pages |
3461-7. |
| |
keywords |
Bacterial Proteins/ultrastructure |
abstract |
Selenocysteine synthase of Escherichia coli catalyses the biosynthesis of selenocysteine in the form of the aminoacyl-tRNA complex, the reaction intermediate being aminoacrylyl-tRNA(sec) covalently bound to the prosthetic group of the enzyme. Selenocysteine synthase and the specific aminoacrylyl-tRNA(sec)-enzyme complex as well as the isolated seryl-tRNA(sec) were investigated in the electron microscope and analysed by means of image processing to a resolution of 2 nm in projection. The stoichiometric composition of the selenocysteine synthase molecule was elucidated by scanning transmission electron microscopic mass determination. The enzyme has a fivefold symmetric structure and consists of 10 monomers arranged in two rings. The tRNA is bound near the margin of the dimeric subunits. Principal component analysis of the tRNA-enzyme complexes revealed that the selenocysteine synthase appears to bind only one seryl-tRNA(sec) per dimer, which is consistent with the result of biochemical binding studies. |
last changed |
2002/11/12 16:17 |
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