Family A3

Family

Summary Holotypes Alignment Tree Genomes Literature

A3A

Summary Holotypes Alignment Tree Genomes Literature

A3B

Summary Holotypes Alignment Genomes Literature

Summary for family A3

Family type peptidaseA03.001 - cauliflower mosaic virus-type peptidase (cauliflower mosaic virus), MEROPS Accession MER0000987 (peptidase unit: 40-130)
Content of familyPeptidase family A3 contains endopeptidases.
History Identifier created: Methods Enzymol. 248:105-120 (1995)
Catalytic typeAspartic
Active siteThe active site residue of family A3 was identified by site-directed mutagenesis as an Asp (Torruella et al., 1989), which is located within a D-T/S-G motif. The CaMV endopeptidase (A03.001) is assumed to be a dimer in analogy to the related retropepsins (A2) and to contain a similar structure with an active site consisting of the loop with the active aspartate and the flaps (Le Grice et al., 1988, Wlodawer et al., 1989).
Activities and specificitiesThe only substrates known for the CaMV endopeptidase are derived from ORFs IV (gag) and V (pol). The peptidase activates itself by cleaving the ORF V polypeptide into a peptidase at the N-terminus and a reverse transcriptase. Several cleavage sites are thought to exist within ORF IV are used by CaMV endopeptidase (A03.001), thus explaining the variety of OFR IV products found in virus particles (Al Anil, 1979); however only the site creating the N-terminus of ORF IV derivative p44 has been identified (Torruella et al., 1989). This is a LeuAla cleavage site found within a highly hydrophobic region. Six cleavage sites in the polyprotein for the rice tungro bacilliform virus peptidase (A03.002) have also been determined (Marmey et al., 2005).
InhibitorsThe CaMV endopeptidase (A03.001) is weakly inhibited by pepstatin (Torruella et al., 1989).
Molecular structureThe is currently no tertiary structure available for any of the members of family A3
ClanAA
Basis of clan assignmentActive site residues for members of this family and family A1 occur in the motif D-T/S-G.
Distribution of family Bacteria -  
Archaea -  
Protozoa -  
Fungi -  
Plants details  
Animals details  
Viruses details  
Biological functionsThe peptidases in family A3 are the polyprotein-processing endopeptidases of the pararetroviruses. These are double-stranded DNA viruses that infect plants. The genome contains an open reading frame (ORF V) that is analogous to the pol gene of retroviruses.
ReviewsHohn, 2004
Statistics for family A3Sequences:61
Identifiers:6
Identifiers with PDB entries:0
Downloadable files Sequence library (FastA format)
Sequence alignment (FastA format)
Phylogenetic tree (Newick format)
Subfamily A3A
Name Peptidase subfamily A3A
Subfamily type peptidase A03.001 - cauliflower mosaic virus-type peptidase (cauliflower mosaic virus), MEROPS Accession MER0000987 (peptidase unit: 40-130)
Active site residues D45 
Statistics Sequences: 49
Identifiers: 5
Identifiers with PDB entries: 0
Other databases INTERPRO IPR000588
PFAM PF00077
PFAM PF02160
PFAM PF13650
Downloadable files Sequence library [FastA format]
Sequence alignment [FastA format]
Phylogenetic tree [Newick format]
Peptidases and Homologues MEROPS ID Structure
cauliflower mosaic virus-type peptidaseA03.001-
banana streak virus peptidaseA03.003-
Commelina yellow mottle virus peptidaseA03.004-
cassava vein mosaic virus-type peptidaseA03.005-
retrotransposon peptidase (Nicotiana-type)A03.006-
subfamily A3A unassigned peptidasesunassigned-
Subfamily A3B
Name Peptidase subfamily A3B
Subfamily type peptidase A03.002 - bacilliform virus peptidase (rice tungro bacilliform virus), MEROPS Accession MER0002148 (peptidase unit: 982-1068)
Active site residues D987 
Statistics Sequences: 2
Identifiers: 1
Identifiers with PDB entries: 0
Other databases INTERPRO IPR001995
PFAM PF02160
Downloadable files Sequence library [FastA format]
Sequence alignment [FastA format]
Peptidases and Homologues MEROPS ID Structure
bacilliform virus peptidaseA03.002-
subfamily A3B unassigned peptidasesunassigned-
Peptidases not assigned to subfamily
Peptidases and Homologues MEROPS ID Structure
family A3 non-peptidase homologuesnon-peptidase homologue-
family A3 unassigned peptidasesunassigned-