Three-dimensional structure of bladder membrane protein

Area of Science:

• Biophysics
• Structural Biology
• Cell Biology

Background:

• Mammalian bladder membranes possess naturally occurring crystalline structures.
• Understanding the structural organization of these membranes is crucial for comprehending their function.

Purpose of the Study:

• To determine the crystallographic structure of mammalian bladder membrane crystals.
• To elucidate the arrangement and distribution of protein subunits within the membrane.

Main Methods:

• Crystallographic analysis of naturally occurring mammalian bladder membrane crystals.
• Three-dimensional (3D) reconstruction using negative stain electron microscopy.
• Comparison with shadowed specimens to identify protein particle location.

Main Results:

• The crystals belong to the two-sided plane group p6 with a lattice parameter of 160 Å.
• 3D reconstruction revealed a motif of twelve subunits, elongated perpendicular to the crystal plane to a height of approximately 50 Å.
• Negative stain revealed protein particles exclusively on one side of the membrane, confirmed by comparison with shadowed specimens.

Conclusions:

• The mammalian bladder membrane exhibits a well-defined crystalline structure.
• The protein subunits are asymmetrically distributed, primarily on one surface of the membrane.
• These findings provide insights into the structural basis of bladder membrane organization and function.