PDBsum entry 4kjd

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protein ligands metals Protein-protein interface(s) links
Hydrolase PDB id
Jmol PyMol
Protein chains
408 a.a.
GOL ×2
_MG ×4
Waters ×277
PDB id:
Name: Hydrolase
Title: Ratintestinal ap expressed in e. Coli
Structure: Intestinal-type alkaline phosphatase 1. Chain: a, b. Synonym: iap-1, intestinal alkaline phosphatase 1, intestin alkaline phosphatase i, iap-i. Engineered: yes
Source: Rattus norvegicus. Brown rat,rat,rats. Organism_taxid: 10116. Gene: alpi. Expressed in: escherichia coli. Expression_system_taxid: 562.
2.21Å     R-factor:   0.169     R-free:   0.203
Authors: K.Ghosh,R.K.Anumula,B.K.Laksmaiah
Key ref: K.Ghosh et al. (2013). Crystal structure of rat intestinal alkaline phosphatase--role of crown domain in mammalian alkaline phosphatases. J Struct Biol, 184, 182-192. PubMed id: 24076154 DOI: 10.1016/j.jsb.2013.09.017
03-May-13     Release date:   16-Oct-13    
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Protein chains
Pfam   ArchSchema ?
P15693  (PPBI1_RAT) -  Intestinal-type alkaline phosphatase 1
540 a.a.
408 a.a.
Key:    PfamA domain  PfamB domain  Secondary structure  CATH domain

 Enzyme reactions 
   Enzyme class: E.C.  - Alkaline phosphatase.
[IntEnz]   [ExPASy]   [KEGG]   [BRENDA]
      Reaction: A phosphate monoester + H2O = an alcohol + phosphate
phosphate monoester
+ H(2)O
= alcohol
+ phosphate
      Cofactor: Mg(2+); Zn(2+)
Molecule diagrams generated from .mol files obtained from the KEGG ftp site
 Gene Ontology (GO) functional annotation 
  GO annot!
  Cellular component     membrane   5 terms 
  Biological process     metabolic process   3 terms 
  Biochemical function     catalytic activity     9 terms  


DOI no: 10.1016/j.jsb.2013.09.017 J Struct Biol 184:182-192 (2013)
PubMed id: 24076154  
Crystal structure of rat intestinal alkaline phosphatase--role of crown domain in mammalian alkaline phosphatases.
K.Ghosh, D.Mazumder Tagore, R.Anumula, B.Lakshmaiah, P.P.Kumar, S.Singaram, T.Matan, S.Kallipatti, S.Selvam, P.Krishnamurthy, M.Ramarao.
Intestinal alkaline phosphatases (IAPs) are involved in the cleavage of phosphate prodrugs to liberate the drug for absorption in the intestine. To facilitate in vitro characterization of phosphate prodrugs, we have cloned, expressed, purified and characterized IAPs from rat and cynomolgus monkey (rIAP and cIAP respectively) which are important pre-clinical species for drug metabolism studies. The recombinant rat and monkey enzymes expressed in Sf9 insect cells (IAP-Ic) were found to be glycosylated and active. Expression of rat IAP in Escherichia coli (rIAP-Ec) led to ∼200-fold loss of activity that was partially recovered by the addition of external Zn(2+) and Mg(2+) ions. Crystal structures of rIAP-Ec and rIAP-Ic were determined and they provide rationale for the discrepancy in enzyme activities. Rat IAP-Ic retains its activity in presence of both Zn(2+) and Mg(2+) whereas activity of most other alkaline phosphatases (APs) including the cIAP was strongly inhibited by excess Zn(2+). Based on our crystal structure, we hypothesized the residue Q317 in rIAP, present within 7Å of the Mg(2+) at M3, to be important for this difference in activity. The Q317H rIAP and H317Q cIAP mutants showed reversal in effect of Zn(2+), corroborating the hypothesis. Further analysis of the two structures indicated a close linkage between glycosylation and crown domain stability. A triple mutant of rIAP, where all the three putative N-linked glycosylation sites were mutated showed thermal instability and reduced activity.