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1xjo

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Molecule : Aminopeptidase Classification : Hydrolase

Organism : Streptomyces Griseus Bound ligands : CA, MHO, PO4, ZN


Contents

Biological function

S. griseus Aminopeptidase (SGAP) (E.C. 3.4.11.-) cleaves the N-terminal amino acid from a peptide or protein, and is specific for larger hydrophobic acids, especially leucine. No cleavage occurs if the next residue is proline.


Structural features

1xjo, resolution 1.75Å ()
Sites: and
Ligands: , ,
Non-Standard Residues:
Domains: PRK12890, Peptidase_M28
Resources: FirstGlance, OCA, PDBsum, RCSB
Coordinates: save as pdb, mmCIF, xml



SGAP belongs to the bacterial dinuclear zinc exopeptidase family and the Zn-dependent exopeptidase superfamily. It has a phosphorylase/hydrolase-like α/β fold, consisting of a 3-layer .

The of the enzyme contains two Zn2+ ions with His85 and Asp160 as ligands for one ion, and Glu132 and His247 as ligands for the second ion. Asp97 is a common ligand to both ions. What appears to be a phosphate anion is bound to both zinc atoms, replacing the water molecule/hydroxide ion normally found in this class of enzyme.

The enzyme's activity is modulated by Calcium cations. This structure revealed a near the N-terminus, involving Ile4, Asp262, Asp266, two water molecules, and Asp3. This site, however, is quite distant from the active site, and it was unclear how this might modulate enzymatic activity. Subsequent mutagenesis studies (Arima et al., 2006a, 2006b) revealed a adjacent to the active site involving Asp173, Asp174, and Glu196. The latter residue was part of the chain (196-202) that could not be seen in electron density maps in 1xjo.

This view illustrates the path the from its amino (N) terminus in blue to its carboxy (C) terminus in red.

Biological context

SGAP belongs to the Peptidase_M28b family, and is one of the many proteinases secreted by S. grisues.

Additional Information

Related structures include by homologous chain: 1f2o, 1f2p.


PDB entry information

Exp. Method: X-ray diffraction

Authors: H.M.Greenblatt, O.Almog, B.Maras, A.Spungin-Bialik, D.Barra, S.Blumberg, G.Shoham

R-value: 0.141 (work)

Date: Jun 23, 1996

Compound Source
Molecule: Aminopeptidase
Chain: A
Synonym: Sgap
Ec: 3.4.11.-
 Organism_scientific: Streptomyces Griseus
Other_details: The Enzyme Is Isolated From The Commercially Available Enzyme Mixture "Pronase E"

Space group: P41212

Crystal cell:

length a length b length c angle alpha angle beta angle gamma
61.810 61.810 146.300 90.00 90.00 90.00

Links

References

  1. Primary: Greenblatt, H.M., Almog, O., Maras, B., Spungin-Bialik, A., Barra, D., Blumberg, S., Shoham, G., (1997) "Streptomyces griseus aminopeptidase: x-ray crystallographic structure at 1.75 a resolution", J. Mol. Biol. 265 (620). PMID: 9048953
  2. Maras, B., Greenblatt, H.M., Shoham, G., Spungin-Bialik, A., Blumberg, S., Barra, D., (1996) "Aminopeptidase from s. griseus: primary structure and comparision with other zinc-containing aminopeptidases", Eur. J. Biochem. 236 (843). PMID: 8665903
  3. Arima J, Uesugi Y, Uraji M, Iwabuchi M, Hatanaka T. The role of Glu196 in the environment around the substrate binding site of leucine aminopeptidase from Streptomyces griseus. FEBS Lett. 2006 Feb 6;580(3):912-7. PMID: 16427629

--Harry 15:45, 13 March 2008 (IST) Authored by H. M. Greenblatt

Proteopedia Page Contributors and Editors (what is this?)

Eran Hodis, Harry Greenblatt, Jaime Prilusky

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