排序方式: 共有1条查询结果,搜索用时 0 毫秒
1
1.
Ertughrul OW; Errington N; Raza S; Sutcliffe MJ; Rowe AJ; Scrutton NS 《Protein engineering, design & selection : PEDS》1998,11(6):447-455
In trimethylamine dehydrogenase, a homodimeric iron-sulfur flavoprotein,
the C-terminal 17 residues of each subunit (residues 713- 729) embrace
residues on the other subunit. The role of this unusual mode of interaction
at the subunit interface was probed by isolating three mutant forms of
trimethylamine dehydrogenase in which the C- terminus of the enzyme was
deleted by five residues [delta(725-729], 10 residues [delta(720-729)] and
17 residues [delta(713-729)]. The solution properties and conformational
states of the three mutant enzymes were investigated using optical,
fluorescence and circular dichroism spectroscopies, ANS binding and a novel
and conformationally sensitive hydrodynamic method. The data reveal that
sequential deletion of the C-terminus of trimethylamine dehydrogenase does
not affect significantly dimer stability or the overall structural
integrity of the enzyme. However, deletion of the C-terminus severely
compromises, but does not abolish, the ability of the enzyme to become
covalently coupled with the redox cofactor FMN in the active site, located
over 20 A from the C-terminus. Hydrodynamic studies reveal minor
conformational changes in the deletion mutants that lead to a more compact
enzyme structure. These conformational changes are probably transmitted to
the active site via altering the interaction of the C-terminus with the
second helix in the beta/alpha barrel of trimethylamine dehydrogenase,
leading to poor flavinylation during the folding of the enzyme and assembly
with FMN.
相似文献
1