Look up a standard endotoxin assay
(usually an immunoassay) because that’s exactly what endotoxin is J
Artem
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When the Weasel comes to give New
Year's greetings to the Chickens no good intentions are in his mind.
From: CCP4 bulletin
board [mailto:[log in to unmask]] On
Behalf Of
Sent: Thursday, February 26, 2009
5:53 PM
To: [log in to unmask]
Subject: [ccp4bb] Questions
regarding Peptidoglycan-binding protein
Dear all,
Thank you in advance for your expert opinions.
I am working on a peptidoglycan (PG)-binding protein, which is composed of two
functionally identical domains. Interestingly, when subjected to gel filtration
chromatography (Superdex 200), both full-length protein and the single domains
migrate as a major peak tailed with a broad shoulder. SDS-PAGE indicates the
expected MW for both samples from the major peak and the shoulder, however,
with the presence of smears at high molecular weight. Also, after all fractions
from both the major peak and the shoulder were combined and incubated at 4 C
over 48 hours, the sample was applied to gel filtration again; this time the
shoulder actually disappeared (or shifted), resulting in a nice symmetric peak (with
the same elution volume as the major peak).
My guess is that the protein expressed in E. coli may already specifically or
unspecifically associate with PG fragments from cell wall. My question is: how to detect PG fragments in my protein sample?
I have tried denaturation-wash-renaturation steps, but I want to know if I have
completely got rid of the possible "contaminants".
Thank you for suggestions.
Joe