Hi, All: Although it is off-topic, definitely I think I can get some help here because we crystallographers are dealing with protein purification almost every day.
My protein was expressed in E.coli as a soluble octamer with or without his-tag revealed by gel-filtration. For the his-tagged protein, the final product is an octamer after Ni-column and gel-fil. However, purification of the non-tagged protein results in a tetramer because of a partially denatured condition. When I tested the enzymatic activity , it turns out the tetramer was active although both of them can be crystallized. Now I am wonderring whether its native form in human is an octamer or tetramer. I am planning to purify a little protein from human cells to verify its native form. Can anybody recommend some protocols? Thanks a million, Jerry McCully _________________________________________________________________ Rediscover HotmailĀ®: Now available on your iPhone or BlackBerry http://windowslive.com/RediscoverHotmail?ocid=TXT_TAGLM_WL_HM_Rediscover_Mobile1_042009