Hi
i have setup a crystallization of a complex formed by two different
proteins of molecular weights 53kD and 13kD. During purification of this
complex there was slight degradation band of 53KD protein as observed from
SDS PAGE but it did not effect complex formation. Crystals appeared after 8
months and on solving the structure i could find only 6kD fragment of the
53kD protein associated in complex form with 13kD protein and the rest of
the fragment remains absent. Mass spec analysis with the crystals gave the
same result. I couldn't explain this anomalous behavior. I have used
different types of protease inhibitors and there is no autodegradation or
autoproteolysis site. Can anyone please suggest what accounts for such
unusual phenomenon. How to identify if any autoproteolysis event is taking
place.
