3MXW

Crystal structure Sonic hedgehog bound to the 5E1 fab fragment

Summary for 3MXW

• Entry DOI: 10.2210/pdb3mxw/pdb
• Related: 1VHH 3M1N 3MXV
• Descriptor: Sonic hedgehog protein, 5E1 light chain, 5E1 heavy chain, ... (7 entities in total)
• Functional Keywords: antibody complex, fab fragment, metalloprotease, calcium binding, zinc hydrolase, development, morphogen, signaling protein
• Biological source: Homo sapiens (human); More
• Cellular location: Sonic hedgehog protein C-product: Secreted, extracellular space (By similarity). Sonic hedgehog protein N-product: Cell membrane; Lipid-anchor (By similarity): Q15465
• Total number of polymer chains: 3
• Total formula weight: 66879.98

Authors

Hymowitz, S.G.,Maun, H.R. (deposition date: 2010-05-07, release date: 2010-05-26, Last modification date: 2024-10-30)

Primary citation

Maun, H.R.,Wen, X.,Lingel, A.,de Sauvage, F.J.,Lazarus, R.A.,Scales, S.J.,Hymowitz, S.G.
Hedgehog pathway antagonist 5E1 binds hedgehog at the pseudo-active site.
J.Biol.Chem., 285:26570-26580, 2010

PubMed Abstract: Proper hedgehog (Hh) signaling is crucial for embryogenesis and tissue regeneration. Dysregulation of this pathway is associated with several types of cancer. The monoclonal antibody 5E1 is a Hh pathway inhibitor that has been extensively used to elucidate vertebrate Hh biology due to its ability to block binding of the three mammalian Hh homologs to the receptor, Patched1 (Ptc1). Here, we engineered a murine:human chimeric 5E1 (ch5E1) with similar Hh-binding properties to the original murine antibody. Using biochemical, biophysical, and x-ray crystallographic studies, we show that, like the regulatory receptors Cdon and Hedgehog-interacting protein (Hhip), ch5E1 binding to Sonic hedgehog (Shh) is enhanced by calcium ions. In the presence of calcium and zinc ions, the ch5E1 binding affinity increases 10-20-fold to tighter than 1 nm primarily because of a decrease in the dissociation rate. The co-crystal structure of Shh bound to the Fab fragment of ch5E1 reveals that 5E1 binds at the pseudo-active site groove of Shh with an epitope that largely overlaps with the binding site of its natural receptor antagonist Hhip. Unlike Hhip, the side chains of 5E1 do not directly coordinate the Zn(2+) cation in the pseudo-active site, despite the modest zinc-dependent increase in 5E1 affinity for Shh. Furthermore, to our knowledge, the ch5E1 Fab-Shh complex represents the first structure of an inhibitor antibody bound to a metalloprotease fold.

PubMed: 20504762
DOI: 10.1074/jbc.M110.112284

Experimental method

X-RAY DIFFRACTION (1.83 Å)