PDBsum entry 1itp

Protein binding

PDB id: 1itp

Contents

Protein chain

77 a.a.

References listed in PDB file

Key reference

Title

Structure of poia1, A homologous protein to the propeptide of subtilisin: implication for protein foldability and the function as an intramolecular chaperone.

Authors

H.Sasakawa, S.Yoshinaga, S.Kojima, A.Tamura.

Ref.

J Mol Biol, 2002, 317, 159-167. [DOI no: 10.1006/jmbi.2002.5412]

PubMed id

11916386

Abstract

Solution structure of POIA1 (Pleurotus ostreatus proteinase A inhibitor 1), which functions as an intramolecular chaperone and as an inhibitor to subtilisin, was determined. By making use of the fact that POIA1 is the only structured protein that shows homology to the propeptide of subtilisin, which is unstructured by itself, foldability of this protein was elucidated. It became clear that the evolutionarily conserved residues play two important roles, one for the maintenance of its own structure, and the other for the interaction with subtilisin. Structural softness and mutational tolerance contained in the POIA1 structure makes it an ideal material for designing a foldable protein.

Figure 3.
Figure 3. (a) Ribbon diagrams of structures of POIA1 (left) and the propeptide of subtilisin BPN′ (right). (b) The electrostatic surface potential of POIA1 and the propeptide. For all the electrostatic potential diagrams, surface color reflects the magnitude and sign of the electrostatic potential (red, negative; blue, positive; white, neutral).

Figure 4.
Figure 4. (a) Hydrophobic residues in the propeptide interacting with subtilisin BPN′ represented by the space-filling model. Residues drawn in magenta (propeptide) and green (subtilisin BPN′) are intermolecularly contacting with each other (based on 1SPB in PDB). (b) Corresponding amino acid residues in POW (magenta). Note that Gly40 is missing since it has no side-chain.

The above figures are reprinted by permission from Elsevier: J Mol Biol (2002, 317, 159-167) copyright 2002.