1l9l

From Proteopedia

Revision as of 14:17, 15 February 2008

GRANULYSIN FROM HUMAN CYTOLYTIC T LYMPHOCYTES

Overview

Our crystal structure of granulysin suggests a mechanism for lysis of, bacterial membranes by granulysin, a 74-residue basic protein from human, cytolytic T lymphocyte and natural killer cells. We determined the initial, crystal structure of selenomethionyl granulysin by MAD phasing at 2A, resolution. We present the structure model refined using native, diffraction data to 0.96A resolution. The five-helical bundle of, granulysin resembles other "saposin folds" (such as NK-lysin). Positive, charges distribute in a ring around the granulysin molecule, and one face, has net positive charge. Sulfate ions bind near the segment of the, molecule identified as most membrane-lytic and of highest hydrophobic, moment. The ion locations may indicate granulysin's orientation of initial, approach towards the membrane. The crystal packing reveals one way to pack, a sheet of granulysin molecules at the cell surface for a concerted lysis, effort. The energy of binding granulysin charges to the bacterial membrane, could drive the subsequent lytic processes. The loosely packed core, facilitates a hinge or scissors motion towards exposure of hydrophobic, surface that we propose tunnels the granulysin into the fracturing target, membrane.

About this Structure

1L9L is a Single protein structure of sequence from Homo sapiens with , and as ligands. Full crystallographic information is available from OCA.

Reference

Granulysin crystal structure and a structure-derived lytic mechanism., Anderson DH, Sawaya MR, Cascio D, Ernst W, Modlin R, Krensky A, Eisenberg D, J Mol Biol. 2003 Jan 10;325(2):355-65. PMID:12488100

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