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The structural homology between uteroglobin and the pore‐forming domain of colicin A suggests a possible mechanism of action for uteroglobin
Author(s) -
Cruz Xavier De La,
Lee B.
Publication year - 1996
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1002/pro.5560050507
Subject(s) - colicin , uteroglobin , biophysics , chemistry , escherichia coli , homology (biology) , crystallography , biology , biochemistry , amino acid , gene
Although the exact physiological function of uteroglobin is not known, it has been suggested that it may function by inhibiting phospholipase A 2 . We have found that the uteroglobin fold is embedded in that of the pore‐forming domain of colicin A. Colicin A is an antibiotic protein that kills sensitive Escherichia coli cells by forming a pore in their phospholipid membrane. The RMS deviation between the C α atoms after the structural alignment is 2.39 Å for the 52 superimposed residues. In the alignment, uteroglobin helices 1, 2, 3, and 4 align with colicin A helices 6, 7, 3, and 4, respectively. The motif is strongly amphipathic in both proteins. On the basis of this common structural motif and of known experimental data on both proteins, we propose that UG binds to the membrane surface by lying on it monotopically. The phospholipase A 2 inhibition would follow this initial binding step.