脂肪酸結合蛋白是一種存在於動物（包括脊椎與無脊椎動物）細胞內的功能性蛋白質。它會結合並運送脂肪酸至不同胞器，特別是粒線體與過氧化體，使脂肪酸被氧化產生能量以維持細胞正常運作。它也會進入細胞核中，雖然還不清楚在細胞核內真正扮演什麼角色，但有相當多的研究顯示脂肪酸結合蛋白也會調控與能量代謝有關的基因表現。脂肪酸結合蛋白有很多種，在演化上來自單一基因，其後經過基因重複的過程而分化出不同種類，在不同組織細胞中也展現不同的功能與特性。在2011年，有研究發現了一種專一表現於螢火蟲發光器官細胞中的脂肪酸結合蛋白，由於過往未曾在生物發光器官中發現此類蛋白質，而螢火蟲發光的調控機制也存在許多未知，因而本論文便以此螢火蟲發光器官之脂肪酸結合蛋白為主題展開研究。
本論文聚焦於瞭解此螢火蟲發光器官之脂肪酸結合蛋白的結構特性，主要貢獻有二：一、解出此蛋白質的三級結構；二、發現第125號的精氨酸突變為丙氨酸後會明顯降低此蛋白質對脂肪酸配體的親和性。在此研究中，筆者利用大腸桿菌表現系統來大量表現重組的螢火蟲發光器官之脂肪酸結合蛋白，其後利用離子交換法與膠體過濾法等液相層析方式純化分離出此蛋白質。結構特性的分析方面則先利用圓二色光譜儀測定其二級結構並探究此蛋白質的熱穩定性，之後利用液態核磁共振光譜的技術解出了此螢火蟲發光器官之脂肪酸結合蛋白的三級結構。在整體構型上，雖然此蛋白質與其它同家族的脂肪酸結合蛋白相像，都具有10個β鏈與2個較短的α螺旋，但它的第四及第五β鏈間的轉折段較長，在三度空間上與配體的出入口相當近，因而很可能會影響對於不同脂肪酸配體的選擇性。另一方面，筆者也利用分子生物學方法得到第125號精氨酸變為丙氨酸的突變體(R125A)，並利用螢光光譜儀比較了野生型與突變體對於脂肪酸配體親和性的差異，此實驗結果顯示R125A對於脂肪酸配體—特別是肉豆蔻酸(14碳鏈長的飽和脂肪酸)—親和性降低，隨後利用電腦模擬計算螢火蟲發光器官之脂肪酸結合蛋白與脂肪酸配體之結合模型，探討第125號精氨酸可能如何影響配體結合的親和性。由於蛋白質的功能與其三級結構息息相關，本研究所解出的螢火蟲發光器官之脂肪酸結合蛋白三級結構可作為未來更進一步探討此蛋白質在螢火蟲發光器官內作用機轉之基礎。

Fatty acid-binding proteins (FABPs), members of the intracellular lipid-binding protein superfamily, are present in both vertebrates and invertebrates and constitute a considerable portion of many energy-consuming cells. FABPs mediate the solubilization and transport of fatty acids in the aqueous environment of the cytosol. FABPs from different invertebrate species have been identified in various tissue types, and many of them have suggested involvement in diverse physiological roles. A novel FABP, lcFABP, was previously characterized in the light organ of Taiwanese firefly Luciola cerata. lcFABP was suggested to supply energy for sustaining bioluminescent flashes by binding and transporting fatty acids; however, the precise molecular mechanisms underlying this process remain elusive as structural information on lcFABP is limited. In this study, the three-dimensional structure of lcFABP was determined by using the solution-state NMR spectroscopy. lcFABP adopts an overall β-clam conformation with ten anti-parallel β-strands and two short α-helices, which agrees with the general structural features of the FABP family. The 10 lowest-energy structures ensemble of lcFABP is of agreeable stereochemical quality and has been deposited to the Protein Data Bank (ID: 2N93). Inspection of the solution structure revealed that lcFABP adopts a unique extended βE-turn-βF stretches which is distinct from other FABPs. On the other hand, comparison of the ligand binding properties between wild-type lcFABP and a mutant, R125A, showed that R125 is crucial in determining ligand binding affinity. The lcFABP-fatty acid docking models have revealed possible interaction scheme between lcFABP and the ligand. These results disclose specific structural characteristics of lcFABP and imply the possible mechanisms underlying lcFABP-mediated ligand binding.

[1] L.J. Kricka, G.H.G. Thorpe, Chemiluminescent and bioluminescent methods in Analytical Chemistry. A review, Analyst, 108 (1983) 1274-1296.
[2] J.B. Buck, The Anatomy and Physiology of the Light Organ in Fireflies, Annals of the New York Academy of Sciences, 49 (1948) 397-485.
[3] J. Buck, J. Case, Physiological Links in Firefly Flash Code Evolution, Journal of Insect Behavior, 15 (2002) 51-68.
[4] K. Gomi, N. Kajiyama, Oxyluciferin, a luminescence product of firefly luciferase, is enzymatically regenerated into luciferin, The Journal of biological chemistry, 276 (2001) 36508-36513.
[5] B.A. Trimmer, J.R. Aprille, D.M. Dudzinski, C.J. Lagace, S.M. Lewis, T. Michel, S. Qazi, R.M. Zayas, Nitric oxide and the control of firefly flashing, Science, 292 (2001) 2486-2488.
[6] M.D. Greenfield, Missing link in firefly bioluminescence revealed: NO regulation of photocyte respiration, BioEssays : news and reviews in molecular, cellular and developmental biology, 23 (2001) 992-995.
[7] V.C. Barber, C.W. Pilcher, An enzyme histochemical and electron microscopical study of the light organ of the glow-worm, Lampyris noctiluca, Q J Microsc Sci, 106 (1965) 247-259.
[8] Y. Oba, M. Ojika, S. Inouye, Firefly luciferase is a bifunctional enzyme: ATP-dependent monooxygenase and a long chain fatty acyl-CoA synthetase, FEBS letters, 540 (2003) 251-254.
[9] K.S. Goh, C.W. Li, A photocytes-associated fatty acid-binding protein from the light organ of adult Taiwanese firefly, Luciola cerata, PloS one, 6 (2011) e29576.
[10] M.I. Gurr, J.L. Harwood, K.N. Frayn, Lipid Biochemistry: An Introduction, 5th ed., Blackwell Science Ltd, Oxford, UK., 2002.
[11] D.E. Vance, J.E. Vance, Biochemistry of Lipids, Lipoproteins and Membranes, Elsevier, Amsterdam, 2002.
[12] J.E. Hunter, Dietary trans fatty acids: review of recent human studies and food industry responses, Lipids, 41 (2006) 967-992.
[13] A. Georgiadi, S. Kersten, Mechanisms of gene regulation by fatty acids, Adv Nutr, 3 (2012) 127-134.
[14] K.M. Eyster, The membrane and lipids as integral participants in signal transduction: lipid signal transduction for the non-lipid biochemist, Advances in physiology education, 31 (2007) 5-16.
[15] A.A. Spector, Fatty acid binding to plasma albumin, Journal of lipid research, 16 (1975) 165-179.
[16] J.F. Glatz, G.J. van der Vusse, Cellular fatty acid-binding proteins: their function and physiological significance, Progress in lipid research, 35 (1996) 243-282.
[17] J. Storch, A.E. Thumser, The fatty acid transport function of fatty acid-binding proteins, Biochimica et biophysica acta, 1486 (2000) 28-44.
[18] J. Li, E. Henry, L. Wang, O. Delelis, H. Wang, F. Simon, P. Tauc, J.C. Brochon, Y. Zhao, E. Deprez, Comparative study of the fatty acid binding process of a new FABP from Cherax quadricarinatus by fluorescence intensity, lifetime and anisotropy, PloS one, 7 (2012) e51079.
[19] C. Lücke, L.H. Gutiérrez-González, J.A. Hamilton, Intracellular Lipid Binding Proteins: Evolution, Structure, and Ligand Binding, Cellular Proteins and Their Fatty Acids in Health and Disease, Wiley-VCH Verlag GmbH & Co. KGaA2004, pp. 95-118.
[20] R.K. Ockner, J.A. Manning, R.B. Poppenhausen, W.K. Ho, A binding protein for fatty acids in cytosol of intestinal mucosa, liver, myocardium, and other tissues, Science, 177 (1972) 56-58.
[21] F.G. Schaap, G.J. van der Vusse, J.F. Glatz, Evolution of the family of intracellular lipid binding proteins in vertebrates, Molecular and cellular biochemistry, 239 (2002) 69-77.
[22] Y. Zheng, D. Blair, J.E. Bradley, Phyletic distribution of fatty acid-binding protein genes, PloS one, 8 (2013) e77636.
[23] A. Esteves, R. Ehrlich, Invertebrate intracellular fatty acid binding proteins, Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology, 142 (2006) 262-274.
[24] M. Furuhashi, G.S. Hotamisligil, Fatty acid-binding proteins: role in metabolic diseases and potential as drug targets, Nature reviews. Drug discovery, 7 (2008) 489-503.
[25] J. Thompson, N. Winter, D. Terwey, J. Bratt, L. Banaszak, The crystal structure of the liver fatty acid-binding protein. A complex with two bound oleates, The Journal of biological chemistry, 272 (1997) 7140-7150.
[26] J.C. Sacchettini, J.I. Gordon, L.J. Banaszak, Crystal structure of rat intestinal fatty-acid-binding protein. Refinement and analysis of the Escherichia coli-derived protein with bound palmitate, Journal of molecular biology, 208 (1989) 327-339.
[27] A.C.M. Young, G. Scapin, A. Kromminga, S.B. Patel, J.H. Veerkamp, J.C. Sacchettini, Structural studies on human muscle fatty acid binding protein at 1.4 å resolution: binding interactions with three C18 fatty acids, Structure, 2 (1994) 523-534.
[28] C. Hohoff, T. Borchers, B. Rustow, F. Spener, H. van Tilbeurgh, Expression, purification, and crystal structure determination of recombinant human epidermal-type fatty acid binding protein, Biochemistry, 38 (1999) 12229-12239.
[29] G.K. Balendiran, F. Schnutgen, G. Scapin, T. Borchers, N. Xhong, K. Lim, R. Godbout, F. Spener, J.C. Sacchettini, Crystal structure and thermodynamic analysis of human brain fatty acid-binding protein, The Journal of biological chemistry, 275 (2000) 27045-27054.
[30] N.H. Haunerland, F. Spener, Properties and physiological significance of fatty acid binding proteins, Advances in Molecular and Cell Biology, Elsevier2003, pp. 99-122.
[31] R.A. Peeters, J.H. Veerkamp, R.A. Demel, Are fatty acid-binding proteins involved in fatty acid transfer?, Biochimica et biophysica acta, 1002 (1989) 8-13.
[32] A.J. Smith, B.R. Thompson, M.A. Sanders, D.A. Bernlohr, Interaction of the adipocyte fatty acid-binding protein with the hormone-sensitive lipase: regulation by fatty acids and phosphorylation, The Journal of biological chemistry, 282 (2007) 32424-32432.
[33] J. Storch, B. Corsico, The emerging functions and mechanisms of mammalian fatty acid-binding proteins, Annual review of nutrition, 28 (2008) 73-95.
[34] N.S. Tan, N.S. Shaw, N. Vinckenbosch, P. Liu, R. Yasmin, B. Desvergne, W. Wahli, N. Noy, Selective cooperation between fatty acid binding proteins and peroxisome proliferator-activated receptors in regulating transcription, Molecular and cellular biology, 22 (2002) 5114-5127.
[35] J.F. Glatz, T. Borchers, F. Spener, G.J. van der Vusse, Fatty acids in cell signalling: modulation by lipid binding proteins, Prostaglandins, leukotrienes, and essential fatty acids, 52 (1995) 121-127.
[36] S.U. Nielsen, F. Spener, Fatty acid-binding protein from rat heart is phosphorylated on Tyr19 in response to insulin stimulation, Journal of lipid research, 34 (1993) 1355-1366.
[37] M.K. Buelt, L.L. Shekels, B.W. Jarvis, D.A. Bernlohr, In vitro phosphorylation of the adipocyte lipid-binding protein (p15) by the insulin receptor. Effects of fatty acid on receptor kinase and substrate phosphorylation, The Journal of biological chemistry, 266 (1991) 12266-12271.
[38] N.H. Haunerland, Transport and Utilization of Lipids in Insect Flight Muscles*, Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology, 117 (1997) 475-482.
[39] G. Alvite, N. Garrido, A. Kun, M. Paulino, A. Esteves, Towards an understanding of Mesocestoides vogae fatty acid binding proteins' roles, PloS one, 9 (2014) e111204.
[40] N.H. Haunerland, X. Chen, P. Andolfatto, J.M. Chisholm, Z. Wang, Developmental changes of FABP concentration, expression, and intracellular distribution in locust flight muscle, Molecular and cellular biochemistry, 123 (1993) 153-158.
[41] J.R. Gerstner, W.M. Vanderheyden, P.J. Shaw, C.F. Landry, J.C. Yin, Cytoplasmic to nuclear localization of fatty-acid binding protein correlates with specific forms of long-term memory in Drosophila, Commun Integr Biol, 4 (2011) 623-626.
[42] J.R. Gerstner, W.M. Vanderheyden, P.J. Shaw, C.F. Landry, J.C. Yin, Fatty-acid binding proteins modulate sleep and enhance long-term memory consolidation in Drosophila, PloS one, 6 (2011) e15890.
[43] L. Cheng, X.K. Jin, W.W. Li, S. Li, X.N. Guo, J. Wang, Y.N. Gong, L. He, Q. Wang, Fatty acid binding proteins FABP9 and FABP10 participate in antibacterial responses in Chinese mitten crab, Eriocheir sinensis, PloS one, 8 (2013) e54053.
[44] S.J. Tan, X. Zhang, X.K. Jin, W.W. Li, J.Y. Li, Q. Wang, Fatty acid binding protein FABP3 from Chinese mitten crab Eriocheir sinensis participates in antimicrobial responses, Fish Shellfish Immunol, 43 (2015) 264-274.
[45] R.S. Sha, C.D. Kane, Z. Xu, L.J. Banaszak, D.A. Bernlohr, Modulation of ligand binding affinity of the adipocyte lipid-binding protein by selective mutation. Analysis in vitro and in situ, The Journal of biological chemistry, 268 (1993) 7885-7892.
[46] C.F. Prinsen, J.H. Veerkamp, Fatty acid binding and conformational stability of mutants of human muscle fatty acid-binding protein, The Biochemical journal, 314 ( Pt 1) (1996) 253-260.
[47] K. Elbing, R. Brent, Media Preparation and Bacteriological Tools, John Wiley and Sons, Inc., United States, 2002.
[48] J.L. Markley, A. Bax, Y. Arata, C.W. Hilbers, R. Kaptein, B.D. Sykes, P.E. Wright, K. Wuthrich, Recommendations for the presentation of NMR structures of proteins and nucleic acids. IUPAC-IUBMB-IUPAB Inter-Union Task Group on the Standardization of Data Bases of Protein and Nucleic Acid Structures Determined by NMR Spectroscopy, Journal of biomolecular NMR, 12 (1998) 1-23.
[49] T.D. Goddard, D.G. Kneller, SPARKY 3, University of California, San Francisco, CS, USA.
[50] Victoria A. Higman, Protein NMR: A Practical Guide.
[51] T.A. Wassenaar, M. van Dijk, N. Loureiro-Ferreira, G. van der Schot, S.J. de Vries, C. Schmitz, J. van der Zwan, R. Boelens, A. Giachetti, L. Ferella, A. Rosato, I. Bertini, T. Herrmann, H.R.A. Jonker, A. Bagaria, V. Jaravine, P. Güntert, H. Schwalbe, W.F. Vranken, J.F. Doreleijers, G. Vriend, G.W. Vuister, D. Franke, A. Kikhney, D.I. Svergun, R.H. Fogh, J. Ionides, E.D. Laue, C. Spronk, S. Jurkša, M. Verlato, S. Badoer, S. Dal Pra, M. Mazzucato, E. Frizziero, A.M.J.J. Bonvin, WeNMR: Structural Biology on the Grid, Journal of Grid Computing, 10 (2012) 743-767.
[52] A.T. Brunger, P.D. Adams, G.M. Clore, W.L. DeLano, P. Gros, R.W. Grosse-Kunstleve, J.S. Jiang, J. Kuszewski, M. Nilges, N.S. Pannu, R.J. Read, L.M. Rice, T. Simonson, G.L. Warren, Crystallography & NMR system: A new software suite for macromolecular structure determination, Acta crystallographica. Section D, Biological crystallography, 54 (1998) 905-921.
[53] R.A. Laskowski, J.A. Rullmannn, M.W. MacArthur, R. Kaptein, J.M. Thornton, AQUA and PROCHECK-NMR: programs for checking the quality of protein structures solved by NMR, Journal of biomolecular NMR, 8 (1996) 477-486.
[54] R. Koradi, M. Billeter, K. Wuthrich, MOLMOL: a program for display and analysis of macromolecular structures, J Mol Graph, 14 (1996) 51-55, 29-32.
[55] E.F. Pettersen, T.D. Goddard, C.C. Huang, G.S. Couch, D.M. Greenblatt, E.C. Meng, T.E. Ferrin, UCSF Chimera--a visualization system for exploratory research and analysis, J Comput Chem, 25 (2004) 1605-1612.
[56] T. Velkov, S. Chuang, J. Wielens, H. Sakellaris, W.N. Charman, C.J. Porter, M.J. Scanlon, The interaction of lipophilic drugs with intestinal fatty acid-binding protein, The Journal of biological chemistry, 280 (2005) 17769-17776.
[57] G.M. Morris, R. Huey, W. Lindstrom, M.F. Sanner, R.K. Belew, D.S. Goodsell, A.J. Olson, AutoDock4 and AutoDockTools4: Automated docking with selective receptor flexibility, J Comput Chem, 30 (2009) 2785-2791.
[58] J.J. Irwin, T. Sterling, M.M. Mysinger, E.S. Bolstad, R.G. Coleman, ZINC: a free tool to discover chemistry for biology, Journal of chemical information and modeling, 52 (2012) 1757-1768.
[59] E. Gasteiger, C. Hoogland, A. Gattiker, S. Duvaud, M.R. Wilkins, R.D. Appel, A. Bairoch, Protein Identification and Analysis Tools on the ExPASy Server, in: John M. Walker (Ed.) The Proteomics Protocols Handbook, Humana Press2005.
[60] G.G. Martin, H. McIntosh Al Fau - Huang, S. Huang H Fau - Gupta, B.P. Gupta S Fau - Atshaves, K.K. Atshaves Bp Fau - Landrock, D. Landrock Kk Fau - Landrock, A.B. Landrock D Fau - Kier, F. Kier Ab Fau - Schroeder, F. Schroeder, The human liver fatty acid binding protein T94A variant alters the structure, stability, and interaction with fibrates.
[61] G. Vogt, P. Argos, Protein thermal stability: hydrogen bonds or internal packing?, Fold Des, 2 (1997) S40-46.
[62] Francis A. Carey, Organic chemistry, 4th ed., McGraw-Hill College, Boston, USA, 2000.
[63] J. Cavanagh, W. J. Fairbrother, A. G. Palmer III, N.J. Skelton, M. Rance, Protein NMR Spectroscopy: Principles and Practice, 2nd ed., Academic Press, USA, 2006.
[64] J.M. Hill, NMR screening for rapid protein characterization in structural proteomics, 426 (2008) 437-446.
[65] D. Lassen, C. Lucke, M. Kveder, A. Mesgarzadeh, J.M. Schmidt, B. Specht, A. Lezius, F. Spener, H. Ruterjans, Three-dimensional structure of bovine heart fatty-acid-binding protein with bound palmitic acid, determined by multidimensional NMR spectroscopy, European journal of biochemistry / FEBS, 230 (1995) 266-280.
[66] C. Lucke, M. Rademacher, A.W. Zimmerman, H.T. van Moerkerk, J.H. Veerkamp, H. Ruterjans, Spin-system heterogeneities indicate a selected-fit mechanism in fatty acid binding to heart-type fatty acid-binding protein (H-FABP), The Biochemical journal, 354 (2001) 259-266.
[67] K. Wuthrich, M. Billeter, W. Braun, Polypeptide secondary structure determination by nuclear magnetic resonance observation of short proton-proton distances, Journal of molecular biology, 180 (1984) 715-740.
[68] A. Lopez-Castilla, R.S. de Menezes, D.A. ED, T.R. Dos Santos, J.R. Pires, (1)H, (15)N and (13)C resonance assignments and secondary structure prediction of Q4D059, a conserved and kinetoplastid-specific hypothetical protein from Trypanosoma cruzi, Biomol NMR Assign, 9 (2015) 161-163.
[69] Y. Shen, F. Delaglio, G. Cornilescu, A. Bax, TALOS+: a hybrid method for predicting protein backbone torsion angles from NMR chemical shifts, Journal of biomolecular NMR, 44 (2009) 213-223.
[70] S.G. Hyberts, M.S. Goldberg, T.F. Havel, G. Wagner, The solution structure of eglin c based on measurements of many NOEs and coupling constants and its comparison with X-ray structures, Protein Sci, 1 (1992) 736-751.
[71] J.K. Sabo, D.W. Keizer, Z.P. Feng, J.L. Casey, K. Parisi, A.M. Coley, M. Foley, R.S. Norton, Mimotopes of apical membrane antigen 1: Structures of phage-derived peptides recognized by the inhibitory monoclonal antibody 4G2dc1 and design of a more active analogue, Infect Immun, 75 (2007) 61-73.
[72] F.M. Herr, J. Aronson, J. Storch, Role of portal region lysine residues in electrostatic interactions between heart fatty acid binding protein and phospholipid membranes, Biochemistry, 35 (1996) 1296-1303.
[73] K.T. Hsu, J. Storch, Fatty acid transfer from liver and intestinal fatty acid-binding proteins to membranes occurs by different mechanisms, The Journal of biological chemistry, 271 (1996) 13317-13323.
[74] R.G. Maatman, M. Degano, H.T. Van Moerkerk, W.J. Van Marrewijk, D.J. Van der Horst, J.C. Sacchettini, J.H. Veerkamp, Primary structure and binding characteristics of locust and human muscle fatty-acid-binding proteins, European journal of biochemistry / FEBS, 221 (1994) 801-810.
[75] A.F. Smith, K. Tsuchida, E. Hanneman, T.C. Suzuki, M.A. Wells, Isolation, characterization, and cDNA sequence of two fatty acid-binding proteins from the midgut of Manduca sexta larvae, The Journal of biological chemistry, 267 (1992) 380-384.
[76] G. Akiduki, S. Imanishi, Establishment of a lipid accumulation model in an insect cell line, Arch Insect Biochem Physiol, 66 (2007) 109-121.
[77] Y. He, X. Yang, H. Wang, R. Estephan, F. Francis, S. Kodukula, J. Storch, R.E. Stark, Solution-state molecular structure of apo and oleate-liganded liver fatty acid-binding protein, Biochemistry, 46 (2007) 12543-12556.
[78] B. Sanson, T. Wang, J. Sun, L. Wang, M. Kaczocha, I. Ojima, D. Deutsch, H. Li, Crystallographic study of FABP5 as an intracellular endocannabinoid transporter, Acta Crystallogr D Biol Crystallogr, 70 (2014) 290-298.
[79] M.E. Hodsdon, D.P. Cistola, Ligand binding alters the backbone mobility of intestinal fatty acid-binding protein as monitored by 15N NMR relaxation and 1H exchange, Biochemistry, 36 (1997) 2278-2290.
[80] L. Banaszak, N. Winter, Z. Xu, D.A. Bernlohr, S. Cowan, T.A. Jones, Lipid-binding proteins: a family of fatty acid and retinoid transport proteins, Advances in protein chemistry, 45 (1994) 89-151.
[81] D. Matulis, C.G. Baumann, V.A. Bloomfield, R.E. Lovrien, 1-anilino-8-naphthalene sulfonate as a protein conformational tightening agent, Biopolymers, 49 (1999) 451-458.
[82] J.J. Ory, L.J. Banaszak, Studies of the ligand binding reaction of adipocyte lipid binding protein using the fluorescent probe 1, 8-anilinonaphthalene-8-sulfonate, Biophys J, 77 (1999) 1107-1116.
[83] C. Lucke, Y. Qiao, H.T. van Moerkerk, J.H. Veerkamp, J.A. Hamilton, Fatty-acid-binding protein from the flight muscle of Locusta migratoria: evolutionary variations in fatty acid binding, Biochemistry, 45 (2006) 6296-6305.
[84] E. Jakobsson, G. Alvite, T. Bergfors, A. Esteves, G.J. Kleywegt, The crystal structure of Echinococcus granulosus fatty-acid-binding protein 1, Biochimica et biophysica acta, 1649 (2003) 40-50.