5BV7

Crystal structure of human LCAT (L4F, N5D) in complex with Fab of an agonistic antibody

Summary for 5BV7

• Entry DOI: 10.2210/pdb5bv7/pdb
• Descriptor: Phosphatidylcholine-sterol acyltransferase, 27C3 light chain, 27C3 heavy chain, ... (8 entities in total)
• Functional Keywords: a/b hydrolase, immune system, hydrolase-immune system complex, hydrolase/immune system
• Biological source: Homo sapiens (Human); More
• Total number of polymer chains: 5
• Total formula weight: 145522.37

Authors

Piper, D.E.,Romanow, W.G.,Thibault, S.T.,Walker, N.P.C. (deposition date: 2015-06-04, release date: 2015-12-16, Last modification date: 2024-10-30)

Primary citation

Gunawardane, R.N.,Fordstrom, P.,Piper, D.E.,Masterman, S.,Siu, S.,Liu, D.,Brown, M.,Lu, M.,Tang, J.,Zhang, R.,Cheng, J.,Gates, A.,Meininger, D.,Chan, J.,Carlson, T.,Walker, N.,Schwarz, M.,Delaney, J.,Zhou, M.
Agonistic Human Antibodies Binding to Lecithin-Cholesterol Acyltransferase Modulate High Density Lipoprotein Metabolism.
J.Biol.Chem., 291:2799-2811, 2016

PubMed Abstract: Drug discovery opportunities where loss-of-function alleles of a target gene link to a disease-relevant phenotype often require an agonism approach to up-regulate or re-establish the activity of the target gene. Antibody therapy is increasingly recognized as a favored drug modality due to multiple desirable pharmacological properties. However, agonistic antibodies that enhance the activities of the target enzymes are rarely developed because the discovery of agonistic antibodies remains elusive. Here we report an innovative scheme of discovery and characterization of human antibodies capable of binding to and agonizing a circulating enzyme lecithin cholesterol acyltransferase (LCAT). Utilizing a modified human LCAT protein with enhanced enzymatic activity as an immunogen, we generated fully human monoclonal antibodies using the XenoMouse(TM) platform. One of the resultant agonistic antibodies, 27C3, binds to and substantially enhances the activity of LCAT from humans and cynomolgus macaques. X-ray crystallographic analysis of the 2.45 Å LCAT-27C3 complex shows that 27C3 binding does not induce notable structural changes in LCAT. A single administration of 27C3 to cynomolgus monkeys led to a rapid increase of plasma LCAT enzymatic activity and a 35% increase of the high density lipoprotein cholesterol that was observed up to 32 days after 27C3 administration. Thus, this novel scheme of immunization in conjunction with high throughput screening may represent an effective strategy for discovering agonistic antibodies against other enzyme targets. 27C3 and other agonistic human anti-human LCAT monoclonal antibodies described herein hold potential for therapeutic development for the treatment of dyslipidemia and cardiovascular disease.

PubMed: 26644477
DOI: 10.1074/jbc.M115.672790

Experimental method

X-RAY DIFFRACTION (2.45 Å)