3s3n3s3n. From Proteopedia. Jump to: navation, search. proteopedia link proteopedia link Crystal structure of the Prototype Foamy Virus (PFV) S217H mutant intasome in complex withPDB Entry - 3S3N (Status - Released) Summary information: Title: Crystal structure of the Prototype Foamy Virus (PFV) S217H mutant intasome in complex with magnesium