PDBsum entry 4iap

Lipid binding protein/ hydrorase

PDB id: 4iap

Contents

Protein chains

256 a.a.

Ligands

SO4 ×8

Waters ×103

PDB id:

4iap

Name:

Lipid binding protein/ hydrorase

Title:

Crystal structure of ph domain of osh3 from saccharomyces cerevisiae

Structure:

Oxysterol-binding protein homolog 3,endolysin,oxysterol- binding protein homolog 3. Chain: a, b. Fragment: ph domain (unp residues 221-317), t4 lysozyme (unp residues 2-161),ph domain (unp residues 237-315). Synonym: lysis protein,lysozyme,muramidase. Engineered: yes. Mutation: yes

Source:

Saccharomyces cerevisiae, enterobacteria phage t4. Baker's yeast. Organism_taxid: 559292, 10665. Strain: atcc 204508 / s288c. Gene: osh3, yhr073w. Expressed in: escherichia coli bl21(de3). Expression_system_taxid: 469008.

Resolution:

2.30Å R-factor: 0.242 R-free: 0.274

Authors:

J.Tong,Y.J.Im

Key ref:

J.Tong et al. (2013). Structure of Osh3 reveals a conserved mode of phosphoinositide binding in oxysterol-binding proteins. Structure, 21, 1203-1213. PubMed id: 23791945 DOI: 10.1016/j.str.2013.05.007

Date:

07-Dec-12 Release date: 31-Jul-13

Protein chains

P00720  (ENLYS_BPT4) -  Endolysin from Enterobacteria phage T4

Seq: 164 a.a.

Struc: 256 a.a.*

Protein chains

P38713  (OSH3_YEAST) -  Oxysterol-binding protein homolog 3 from Saccharomyces cerevisiae (strain ATCC 204508 / S288c)

Seq: 996 a.a.

Struc: 256 a.a.*

* PDB and UniProt seqs differ at 172 residue positions (black crosses)

Enzyme reactions

• Enzyme class: E.C.3.2.1.17 - lysozyme.
• Reaction: Hydrolysis of the 1,4-beta-linkages between N-acetyl-D-glucosamine and N-acetylmuramic acid in peptidoglycan heteropolymers of the prokaryotes cell walls.

DOI no: 10.1016/j.str.2013.05.007

Structure 21:1203-1213 (2013)

PubMed id: 23791945

Structure of Osh3 reveals a conserved mode of phosphoinositide binding in oxysterol-binding proteins.

J.Tong, H.Yang, H.Yang, S.H.Eom, Y.J.Im.

ABSTRACT

The oxysterol-binding protein (OSBP)-related proteins (ORPs) are conserved from yeast to humans, and implicated in the regulation of lipid homeostasis and in signaling pathways. Saccharomyces cerevisiae has seven ORPs (Osh1-Osh7) that share one unknown essential function. Here, we report the 1.5-2.3 Å structures of the PH domain and ORD (OSBP-related domain) of yeast Osh3 in apo-form or in complex with phosphatidylinositol 4-phosphate (PI[4]P). Osh3 recognizes PI(4)P by the highly conserved residues in the tunnel of ORD whereas it lacks sterol binding due to the narrow hydrophobic tunnel. Yeast complementation tests suggest that PI(4)P binding to PH and ORD is essential for function. This study suggests that the unifying feature in all ORP homologs is the binding of PI(4)P to ORD and sterol binding is additional to certain homologs. Structural modeling of full-length Osh3 is consistent with the concept that Osh3 is a lipid transfer protein or regulator in membrane contact sites.