PROSITE documentation PDOC51360
Plus3 domain profile


The yeast Paf1 complex consists of Pfa1, Rtf1, Cdc73, Ctr9, and Leo1 and regulates histone H2B ubiquitination, histone H3 methylation, RNA polymerase II carboxy-terminal domain (CTD) Ser2 phosphorylation, and RNA 3' end processing. The conservation of Paf1 complex function in higher eukaryotes has been confirmed in human cells, Drosophila and Arabidopsis. The Plus3 domain spans the most conserved regions of the Rtf1 protein and is surrounded by regions of low complexity and coiled-coil propensity. It contains only a limited number of highly conserved amino acids, among which are three positively charged residues that gave the Plus3 domain its name. The capacity to bind single-stranded DNA is at least one function of the Plus3 domain [1].

The Plus3 domain structure consists of six α helices intervened by a sequence of six β strands in a mixed α/β topology (see <PDB:2BZE>). β strands 1, 2, 5, and 6 compose a four-stranded antiparallel β sheet with a β-hairpin insertion formed by strands 3 and 4. The N-terminal helices α1-α3 and C-terminal helix α6 pack together to form an α subdomain, while the β strands and the small 3(10) helix α 4 form a β subdomain. The two subdomains pack together to form a compact, globular protein [1].

The profile we developed covers the entire Plus3 domain.

Last update:

January 2008 / First entry.


Technical section

PROSITE method (with tools and information) covered by this documentation:

PLUS3, PS51360; Plus3 domain profile  (MATRIX)


1Authorsde Jong R.N. Truffault V. Diercks T. Ab E. Daniels M.A. Kaptein R. Folkers G.E.
TitleStructure and DNA binding of the human rtf1 plus3 domain.
SourceStructure 16:149-159(2008).
PubMed ID18184592

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