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4  structures 2  species 3  interactions 17  sequences 1  architecture

Family: CarbpepA_inh (PF02977)

Summary: Carboxypeptidase A inhibitor

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Carboxypeptidase A inhibitor Edit Wikipedia article

Carboxypeptidase A inhibitor
PDB 4cpa EBI.jpg
refined crystal structure of the potato inhibitor complex of carboxypeptidase a at 2.5 angstroms resolution
Symbol CarbpepA_inh
Pfam PF02977
Pfam clan CL0096
InterPro IPR004231
SCOP 4cpa

In molecular biology, the carboxypeptidase A inhibitor family is a family of proteins which is represented by the well-characterised metallocarboxypeptidase A inhibitor (MCPI) from potatoes, which belongs to the MEROPS inhibitor family I37, clan IE. It inhibits metallopeptidases belonging to MEROPS peptidase family M14, carboxypeptidase A. In Russet Burbank potatoes, it is a mixture of approximately equal amounts of two polypeptide chains containing 38 or 39 amino acid residues. The chains differ in their amino terminal sequence only [1] and are resistant to fragmentation by proteases.[2] The structure of the complex between bovine carboxypeptidase A and the 39-amino-acid carboxypeptidase A inhibitor from potatoes has been determined at 2.5-Angstrom resolution.[3]

The potato inhibitor is synthesised as a precursor, having a 29 amino acid N-terminal signal peptide, a 27 amino acid pro-peptide, the 39 amino acid mature inhibitor region and a 7 amino acid C-terminal extension. The 7 amino acid C-terminal extension is involved in inhibitor inactivation and may be required for targeting to the vacuole where the mature active inhibitor accumulates.[4]

The N-terminal region and the mature inhibitor are weakly related to other solananaceous proteins found in this family, from potato, tomato and henbane, which have been incorrectly described as metallocarboxypeptidase inhibitors.[5]


  1. ^ Hass GM, Nau H, Biemann K, Grahn DT, Ericsson LH, Neurath H (March 1975). "The amino acid sequence of a carboxypeptidase inhibitor from potatoes". Biochemistry 14 (6): 1334–42. doi:10.1021/bi00677a036. PMID 1122280. 
  2. ^ Leary TR, Grahn DT, Neurath H, Hass GM (May 1979). "Structure of potato carboxypeptidase inhibitor: disulfide pairing and exposure of aromatic residues". Biochemistry 18 (11): 2252–6. doi:10.1021/bi00578a018. PMID 444453. 
  3. ^ Rees DC, Lipscomb WN (August 1980). "Structure of the potato inhibitor complex of carboxypeptidase A at 2.5-A resolution". Proc. Natl. Acad. Sci. U.S.A. 77 (8): 4633–7. doi:10.1073/pnas.77.8.4633. PMC 349899. PMID 6933511. 
  4. ^ Villanueva J, Canals F, Prat S, Ludevid D, Querol E, Aviles FX (November 1998). "Characterization of the wound-induced metallocarboxypeptidase inhibitor from potato. cDNA sequence, induction of gene expression, subcellular immunolocalization and potential roles of the C-terminal propeptide". FEBS Lett. 440 (1-2): 175–82. doi:10.1016/S0014-5793(98)01447-1. PMID 9862450. 
  5. ^ Molnar A, Lovas A, Banfalvi Z, Lakatos L, Polgar Z, Horvath S (June 2001). "Tissue-specific signal(s) activate the promoter of a metallocarboxypeptidase inhibitor gene family in potato tuber and berry". Plant Mol. Biol. 46 (3): 301–11. PMID 11488477. 

External links

This article incorporates text from the public domain Pfam and InterPro IPR004231

This page is based on a Wikipedia article. The text is available under the Creative Commons Attribution/Share-Alike License.

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Literature references

  1. Rees DC, Lipscomb WN; , J Mol Biol 1982;160:475-498.: Refined crystal structure of the potato inhibitor complex of carboxypeptidase A at 2.5 A resolution. PUBMED:7154070 EPMC:7154070

External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR004231

In molecular biology, the carboxypeptidase A inhibitor family is a family of proteins which is represented by the well-characterised metallocarboxypeptidase A inhibitor (MCPI) from potatoes, which belongs to the MEROPS inhibitor family I37, clan IE. It inhibits metallopeptidases belonging to MEROPS peptidase family M14, carboxypeptidase A.

Proteins with this domain include metallocarboxypeptidase inhibitor (MCPI) and fruit-specific protein. MCPI may play a defensive role against insect attacks [PUBMED:1715974].

Domain organisation

Below is a listing of the unique domain organisations or architectures in which this domain is found. More...

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Pfam Clan

This family is a member of clan Pept_Inhib_IE (CL0096), which has the following description:

The members of this clan are all cystine rich domains, which form a knottin scaffold. This clan should also contain alpha-amylase but currently this family is a singleton and can not be put into Pfam. Also see [1].

The clan contains the following 2 members:

CarbpepA_inh Squash


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Curation and family details

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Seed source: Structural domain
Previous IDs: none
Type: Domain
Author: Griffiths-Jones SR
Number in seed: 7
Number in full: 17
Average length of the domain: 42.90 aa
Average identity of full alignment: 35 %
Average coverage of the sequence by the domain: 54.44 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 11927849 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 21.5 21.5
Trusted cut-off 24.0 24.5
Noise cut-off 21.4 21.1
Model length: 46
Family (HMM) version: 12
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Species distribution

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There are 3 interactions for this family. More...

CarbpepA_inh Peptidase_M14 Peptidase_M14


For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the CarbpepA_inh domain has been found. There are 4 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein seqence.

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