Use of cross-linking in studying the structure of RNA tumour viruses

Treatment of intact avian myeloblastosis virus (AMV) with dimethyl suberimidate dihydrochloride (DMS), a cross-linking agent specific for amino groups, was found to result in progressive cross-linking among viral proteins, as revealed by polyacrylamide gel electrophoresis (PAGE) in the presence of sodium dodecyl sulphate (SDS). Free viral proteins were not cross-linked. The cross-linked protein complex with an apparent molecular weight of 50,000 daltons was studied in detail.