کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
2052488 1074231 2006 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
The membrane bound bacterial lipocalin Blc is a functional dimer with binding preference for lysophospholipids
موضوعات مرتبط
علوم زیستی و بیوفناوری علوم کشاورزی و بیولوژیک دانش گیاه شناسی
پیش نمایش صفحه اول مقاله
The membrane bound bacterial lipocalin Blc is a functional dimer with binding preference for lysophospholipids
چکیده انگلیسی

Lipocalins, a widespread multifunctional family of small proteins (15–25 kDa) have been first described in eukaryotes and more recently in Gram-negative bacteria. Bacterial lipocalins belonging to class I are outer membrane lipoproteins, among which Blc from E. coli is the better studied. Blc is expressed under conditions of starvation and high osmolarity, conditions known to exert stress on the cell envelope. The structure of Blc that we have previously solved (V. Campanacci, D. Nurizzo, S. Spinelli, C. Valencia, M. Tegoni, C. Cambillau, FEBS Lett. 562 (2004) 183–188.) suggested its possible role in binding fatty acids or phospholipids. Both physiological and structural data on Blc, therefore, point to a role in storage or transport of lipids necessary for membrane maintenance. In order to further document this hypothesis for Blc function, we have performed binding studies using fluorescence quenching experiments. Our results indicate that dimeric Blc binds fatty acids and phospholipids in a micromolar Kd range. The crystal structure of Blc with vaccenic acid, an unsaturated C18 fatty acid, reveals that the binding site spans across the Blc dimer, opposite to its membrane anchored face. An exposed unfilled pocket seemingly suited to bind a polar group attached to the fatty acid prompted us to investigate lyso-phospholipids, which were found to bind in a nanomolar Kd range. We discuss these findings in terms of a potential role for Blc in the metabolism of lysophospholipids generated in the bacterial outer membrane.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: FEBS Letters - Volume 580, Issue 20, 4 September 2006, Pages 4877–4883
نویسندگان
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