BACKGROUND: Papillomaviruses undergo a complex life cycle requiring regulated DNA replication. The papillomavirus E1 helicase is essential for viral DNA replication and plays a key role in controlling viral genome copy number. The E1 helicase is regulated at least in part by protein phosphorylation, however no systematic approach to @entity1391 site mapping has been attempted. We have utilized mass spectrometry of purified @entity291 papillomavirus E1 protein to identify and characterize new sites of phosphorylation. RESULTS: Mass spectrometry and in silico sequence analysis were used to identify @entity1391 sites on the @entity15882 E1 protein and kinases that may recognize these sites. Five new and two previously known phosphorylation sites were identified. A @entity1391 site map was created and used to develop a general model for the role of phosphorylation in E1 function. CONCLUSION: Mass spectrometric analysis identified seven phosphorylated @entity1522 on the @entity15882 E1 protein. Taken with three previously identified sites, there are at least ten @entity13269 on @entity15882 E1. A number of kinases were identified by sequence analysis that could potentially phosphorylate E1 at the identified positions. Several of these kinases have known roles in regulating cell cycle progression. A @entity15882 E1 @entity1391 map and a discussion of the possible role of phosphorylation in E1 function are presented.

A phosphorylation map of the XXXX papillomavirus E1 helicase.

@entity1522 :: ('CHEBI:33709', 'Chemical') :: ['amino acids'] @entity13269 :: ('CHEBI:26051', 'Chemical') :: ['phosphoamino acids'] @entity1391 :: ('CHEBI:26020', 'Chemical') :: ['phosphate'] @entity15882 :: ('10784', 'Species') :: ['BPV'] @entity291 :: ('9913', 'Species') :: ['bovine']
@entity291 :: (9913,Species) :: ['bovine']
