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20  structures 21  species 0  interactions 2209  sequences 43  architectures

Clan: VSA (CL0656)


Variant surface antigens Add an annotation

Members of this clan belong to variant surface antigens (VSA). They are gene products encoded by multi-copy gene families. Four of the largest multi-copy gene families found in the genome of P. falciparum are designated as var, rif (repetitive interspersed family), stevor (subtelomeric variable open reading frame) and pfmc-2tm (P. falciparum Maurer's clefts 2 transmembrane). They code for variable proteins termed PfEMP1 (P. falciparum erythrocyte membrane protein 1), RIFIN, STEVOR and PfMC-2TM, respectively. All small VSA proteins contain a signal peptide and a PEXEL/HT motif. This characteristic as well as their large number and hypervariability support their suggested role in antigenic variation. Antigenic variation and sequestration are strategies used by the malaria parasite P. falciparum to evade antibody mediated immune recognition and splenic clearance [1].

This clan contains 2 families and the total number of domains in the clan is 2209. The clan was built by S El-Gebali.

Literature references

  1. Bachmann A, Scholz JA, Janssen M, Klinkert MQ, Tannich E, Bruchhaus I, Petter M;, Malar J. 2015;14:274.: A comparative study of the localization and membrane topology of members of the RIFIN, STEVOR and PfMC-2TM protein families in Plasmodium falciparum-infected erythrocytes. PUBMED:26173856 EPMC:26173856


This clan contains the following 2 member families:

RIFIN Stevor

Domain organisation

Below is a listing of the unique domain organisations or architectures from this clan. More...

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The table below shows the number of occurrences of each domain throughout the sequence database. More...

Pfam family Num. domains Alignment
RIFIN (PF02009) 1782 (80.7%) View
Stevor (PF17410) 427 (19.3%) View
Total: 2 Total: 2209 Clan alignment

Please note: Clan alignments can be very large and can cause problems for some browsers. Read the note above before viewing.

Family relationships

This diagram shows the relationships between members of this clan. More...

Species distribution

Tree controls


This tree shows the occurrence of the domains in this clan across different species. More...



For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the MSD group, to allow us to map Pfam domains onto UniProt three-dimensional structures. The table below shows the mapping between the Pfam families in this clan, the corresponding UniProt entries, and the region of the three-dimensional structures that are available for that sequence.

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