1EM2

Star-related lipid transport domain of MLN64

Summary for 1EM2

• Entry DOI: 10.2210/pdb1em2/pdb
• Descriptor: MLN64 PROTEIN, D(-)-TARTARIC ACID (3 entities in total)
• Functional Keywords: beta barrel, lipid binding protein
• Biological source: Homo sapiens (human)
• Cellular location: Late endosome membrane; Multi-pass membrane protein: Q14849
• Total number of polymer chains: 1
• Total formula weight: 26263.23

Authors

Tsujishita, Y.,Hurley, J.H. (deposition date: 2000-03-14, release date: 2000-05-02, Last modification date: 2024-11-13)

Primary citation

Tsujishita, Y.,Hurley, J.H.
Structure and lipid transport mechanism of a StAR-related domain.
Nat.Struct.Biol., 7:408-414, 2000

PubMed Abstract: The steroidogenic acute regulatory protein (StAR) regulates acute steroidogenesis in the adrenal cortex and gonads by promoting the translocation of cholesterol to the mitochondrial inner membrane where the first step in steriod biosynthesis is catalyzed. StAR-related lipid transfer (START) domains occur in proteins involved in lipid transport and metabolism, signal transduction, and transcriptional regulation. The 2.2 A resolution crystal structure of the START domain of human MLN64 reported here reveals an alpha/beta fold built around a U-shaped incomplete beta-barrel. The interior of the protein encompasses a 26 x 12 x 11 A hydrophobic tunnel that is large enough to bind a single cholesterol molecule. The StAR and MLN64 START domains bind 1 mole of 14C cholesterol per mole of protein in vitro. Based on the START domain structure and cholesterol binding stoichiometry, it is proposed that StAR acts by shuttling cholesterol molecules one at a time through the intermembrane space of the mitochondrion.

PubMed: 10802740
DOI: 10.1038/75192

Experimental method

X-RAY DIFFRACTION (2.2 Å)