Identification and characterization of the lipid-binding property of GrlR, a locus of enterocyte effacement regulator

TY - JOUR

T1 - Identification and characterization of the lipid-binding property of GrlR, a locus of enterocyte effacement regulator

AU - Jobichen, Chacko

AU - Fernandis, Aaron Z.

AU - Velazquez-Campoy, Adrian

AU - Leung, Ka Yin

AU - Mok, Yu Keung

AU - Wenk, Markus R.

AU - Sivaraman, J.

PY - 2009/6/1

Y1 - 2009/6/1

N2 - Lipocalins are a broad family of proteins identified initially in eukaryotes and more recently in Gram-negative bacteria. The functions of lipocalin or lipid-binding proteins are often elusive and very diverse. Recently, we have determined the structure of GrlR (global regulator of LEE repressor), which plays a key role in the regulation of LEE (locus of enterocyte effacement) proteins. GrlR adopts a lipocalin-like fold that is composed of an eight-stranded β-barrel followed by an α-helix at the C-terminus. GrlR has a highly hydrophobic cavity region and could be a potential transporter of lipophilic molecules. To verify this hypothesis, we carried out structure-based analysis of GrlR, determined the structure of the lipid-GrlR complex and measured the binding of lipid to recombinant GrlR by ITC (isothermal titration calorimetry). In addition, we identified phosphatidylglycerol and phosphatidylethanolamine as the endogenously bound lipid species of GrlR using electrospray-ionization MS. Furthermore, we have shown that the lipid-binding property of GrlR is similar to that of its closest lipocalin structural homologue, β-lactoglobulin. Our studies demonstrate the hitherto unknown lipid-binding property of GrlR.

AB - Lipocalins are a broad family of proteins identified initially in eukaryotes and more recently in Gram-negative bacteria. The functions of lipocalin or lipid-binding proteins are often elusive and very diverse. Recently, we have determined the structure of GrlR (global regulator of LEE repressor), which plays a key role in the regulation of LEE (locus of enterocyte effacement) proteins. GrlR adopts a lipocalin-like fold that is composed of an eight-stranded β-barrel followed by an α-helix at the C-terminus. GrlR has a highly hydrophobic cavity region and could be a potential transporter of lipophilic molecules. To verify this hypothesis, we carried out structure-based analysis of GrlR, determined the structure of the lipid-GrlR complex and measured the binding of lipid to recombinant GrlR by ITC (isothermal titration calorimetry). In addition, we identified phosphatidylglycerol and phosphatidylethanolamine as the endogenously bound lipid species of GrlR using electrospray-ionization MS. Furthermore, we have shown that the lipid-binding property of GrlR is similar to that of its closest lipocalin structural homologue, β-lactoglobulin. Our studies demonstrate the hitherto unknown lipid-binding property of GrlR.

KW - Global regulator of LEE (locus of enterocyte effacement) repressor (Gr1R)

KW - Lipid

KW - Lipocalin

KW - Type III secretion system (T3SS)

KW - β-barrel protein

UR - http://www.scopus.com/inward/record.url?scp=66549126907&partnerID=8YFLogxK

U2 - 10.1042/BJ20081588

DO - 10.1042/BJ20081588

M3 - 文章

C2 - 19228114

AN - SCOPUS:66549126907

SN - 0264-6021

VL - 420

SP - 191

EP - 199

JO - Biochemical Journal

JF - Biochemical Journal

IS - 2

ER -