A Covalent Linker Allows for Membrane Targeting of an Oxylipin Biosynthetic Complex.
In: Biochemistry, Jg. 47 (2008-10-07), Heft 40, S. 10665-10676
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Zugriff:
A naturally occurring bifunctional protein from Plexaura homomalla links sequential catalytic activities in an oxylipin biosynthetic pathway. The C-terminal lipoxygenase (LOX) portion of the molecule catalyzes the transformation of arachidonic acid (AA) to the corresponding 8R-hydroperoxide, and the N-terminal allene oxide synthase (AOS) domain promotes the conversion of the hydroperoxide intermediate to the product allene oxide (AO). Small-angle X-ray scattering data indicate that in the absence of a covalent linkage the two catalytic domains that transform AA to AO associate to form a complex that recapitulates the structure of the bifunctional protein. The SAXS data also support a model for LOX and AOS domain orientation in the fusion protein inferred from a low-resolution crystal structure. However, results of membrane binding experiments indicate that covalent linkage of the domains is required for Ca2+-dependent membrane targeting of the sequential activities, despite the noncovalent domain association. Furthermore, membrane targeting is accompanied by a conformational change as monitored by specific proteolysis of the linker that joins the AOS and LOX domains. Our data are consistent with a model in which Ca2+-dependent membrane binding relieves the noncovalent interactions between the AOS and LOX domains and suggests that the C2-like domain of LOX mediates both protein-protein and protein-membrane interactions. [ABSTRACT FROM AUTHOR]
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A Covalent Linker Allows for Membrane Targeting of an Oxylipin Biosynthetic Complex.
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Autor/in / Beteiligte Person: | Gilbert, Nathaniel C. ; Niebuhr, Marc ; Tsuruta, Hiro ; Bordelon, Tee ; Ridderbusch, Oswin ; Dassey, Adam ; Brash, Alan R. ; Bartlett, Sue G. ; Newcomer, Marcia E. |
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Zeitschrift: | Biochemistry, Jg. 47 (2008-10-07), Heft 40, S. 10665-10676 |
Veröffentlichung: | 2008 |
Medientyp: | academicJournal |
ISSN: | 0006-2960 (print) |
DOI: | 10.1021/bi800751p |
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