caa a22 4500 477119026 CHVBK 20180405111630.0 cr unu---uuuuu 170330e19960601xx s 000 0 eng 10.1007/BF00226061 doi (NATIONALLICENCE)springer-10.1007/BF00226061 Binding site polarity and ligand affinity of homologous fatty acid-binding proteins from animals with different body temperatures [Elektronische Daten] [Richard Londraville, Judith Storch, Bruce Sidell] Binding affinity and binding-pocket polarity is determined for intracellular fatty acid- binding protein (FABP) from aerobic muscle of Chaenocephalus aceratus, the Antarctic icefish, and from rat heart. FABPs bind fatty acids via weak-bond forces (both ionic and hydrophobic), and these bond forces are temperature sensitive, yet FABPs are present in animals whose body temperatures range over nearly 40°C. To investigate FABPs sensitivity to body temperature, fatty acid binding affinity (Kd) was determined for both rat heart-FABP and icefish heart-FABP at two physiological temperatures (0°C or 37°C). Saturated and unsaturated fatty acids (16:0 and 16:1), delivered in model membranes (liposomes) whose composition is typical of either Antarctic fish (16:0/22:6 phosphatidylcholine) or mammals (bovine-heart phosphatidylcholine) were examined. Incubation at 0°C or 37°C does not significantly affect Kd for rat heart FABP, regardless of liposome composition or fatty acid ligand (Kd = 0.686 ± 0.127 - 1.129 ± 0.356 μM at 0°C, 0.775 ± 0.307 - 1.605 ± 0.427 gM at 37°C). Incubation temperature significantly affects icefish FABPs affinity for 16:1 (0.626 ± 0.093 μM at 37°C vs. 1.896 ± 0.343 μM at 0°C for fatty acid presented in Antarctic fish liposomes; 0.331 ± 0.101 μM at 37°C vs. 0.949 ± 0.121 μM at 0°C for bovine heart liposomes) but not 16:0. Kd is not significantly different between FABPs under any set of conditions (with one exception: Kd is significantly lower in rat FABP vs. icefish FABP for 16:0 at 0°C for fatty acids delivered in bovine heart liposomes). Although Kd values are largely equivalent between the two FABPs, relative contributions from ionic vs. hydrophobic weak-bond forces are different between the two animals. Rat heart FABP has a binding pocket that is significantly more nonpolar than that of icefish FABP (as measured by quantum yield of the bound fluorescent fatty-acid analogue (PA-DPH); Q = 0.067 ± 0.008 vs. 0.034 ± 0.005 at 0°C, 0.030 ± 0.003 vs. 0.019 ± 0.002 at 37°C). This suggests that rat-heart FABP realizes a micromolar Kd with a greater reliance upon hydrophobic interactions than does icefish FABP. Kluwer Academic Publishers, 1996 β-oxidation nationallicence free fatty acid nationallicence cold adaptation nationallicence dissociation constant nationallicence fat metabolism nationallicence hydrophobic interaction nationallicence binding pocket nationallicence Londraville Richard Rutgers University Department of Nutritional Sciences, Cook College, 08903, New Brunswick, NJ aut Storch Judith Rutgers University Department of Nutritional Sciences, Cook College, 08903, New Brunswick, NJ aut Sidell Bruce Department of Zoology and Center for Marine Studies, University of Maine, Murray Hall, 04469-5751, Orono, ME, USA aut Molecular and Cellular Biochemistry Kluwer Academic Publishers 159/1(1996-06-01), 39-45 0300-8177 159:1<39 1996 159 11010 https://doi.org/10.1007/BF00226061 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00226061 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Londraville Richard Rutgers University Department of Nutritional Sciences, Cook College, 08903, New Brunswick, NJ aut NATIONALLICENCE 700 1- Storch Judith Rutgers University Department of Nutritional Sciences, Cook College, 08903, New Brunswick, NJ aut NATIONALLICENCE 700 1- Sidell Bruce Department of Zoology and Center for Marine Studies, University of Maine, Murray Hall, 04469-5751, Orono, ME, USA aut NATIONALLICENCE 773 0- Molecular and Cellular Biochemistry Kluwer Academic Publishers 159/1(1996-06-01), 39-45 0300-8177 159:1<39 1996 159 11010 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer