Hello Todd,
if your protein is a cytosolic protein (reductive environment; for ER,
Golgi, mitochondria things look different), the disulfide bond formation
you observe is most probably the result of the oxidative environment
(outside the cell) in combination with the crystal packing that that
brings the two cysteins in close proximity.
J.
Am 20.12.14 um 18:52 schrieb Todd Jason Green:
Hello All-
I have recently determined a domain structure of a larger protein. The
structure shows a clear disulfide bond between two monomers in the
asymmetric unit. I'm trying to figure out if this is an artifact of
the crystal packing or has biological relevance. The protein has been
reported to function as a monomer. If I look at the pool of protein on
a SDS-PAGE gel under non-reducing conditions, I see that a smaller
percentage (~15-20%) of the protein runs as a dimer. In the structure,
the association has 2-fold symmetry with about 29% of the monomeric
surface area buried between the dimer. Can anyone point me in the
direction of a paper describing a non-specific disulfide in a crystal,
or perhaps a criteria for assessing specificity? I will do some
functional studies, but I'm looking for some info on a lazy saturday.
Thanks in advance. Best-
Todd
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Dr.Jeroen R. Mesters
Deputy, Senior Researcher & Lecturer
Institute of Biochemistry, University of Lübeck
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phone: +49-451-5004065 (secretariate 5004061)
fax: +49-451-5004068
http://www.biochem.uni-luebeck.de <Http://www.biochem.uni-luebeck.de>
http://www.iobcr.org <Http://www.iobcr.org>
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