6HA4

Crystal structure of PAF - p-sulfonatocalix[4]arene complex

Summary for 6HA4

• Entry DOI: 10.2210/pdb6ha4/pdb
• Descriptor: Pc24g00380 protein, GLYCEROL, 25,26,27,28-tetrahydroxypentacyclo[19.3.1.1~3,7~.1~9,13~.1~15,19~]octacosa-1(25),3(28),4,6,9(27),10,12,15(26),16,18,21,23-dodecaene-5,11,17,23-tetrasulfonic acid, ... (4 entities in total)
• Functional Keywords: penicillium chrysogenum, antifungal protein, calixarene, molecular glues, nucleating agent
• Biological source: Penicillium rubens (strain ATCC 28089 / DSM 1075 / NRRL 1951 / Wisconsin 54-1255)
• Total number of polymer chains: 1
• Total formula weight: 7099.93

Authors

Alex, J.M.,Rennie, M.,Engilberge, S.,Batta, G.,Crowley, P.B. (deposition date: 2018-08-07, release date: 2019-02-13, Last modification date: 2024-11-06)

Primary citation

Alex, J.M.,Rennie, M.L.,Engilberge, S.,Lehoczki, G.,Dorottya, H.,Fizil, A.,Batta, G.,Crowley, P.B.
Calixarene-mediated assembly of a small antifungal protein.
Iucrj, 6:238-247, 2019

PubMed Abstract: Synthetic macrocycles such as calixarenes and cucurbiturils are increasingly applied as mediators of protein assembly and crystallization. The macrocycle can facilitate assembly by providing a surface on which two or more proteins bind simultaneously. This work explores the capacity of the sulfonato-calix[]arene (sclx ) series to effect crystallization of PAF, a small, cationic antifungal protein. Co-crystallization with sclx, sclx or sclx led to high-resolution crystal structures. In the absence of sclx , diffraction-quality crystals of PAF were not obtained. Interestingly, all three sclx were bound to a similar patch on PAF. The largest and most flexible variant, sclx, yielded a dimer of PAF. Complex formation was evident in solution via NMR and ITC experiments, showing more pronounced effects with increasing macrocycle size. In agreement with the crystal structure, the ITC data suggested that sclx acts as a bidentate ligand. The contributions of calixarene size/conformation to protein recognition and assembly are discussed. Finally, it is suggested that the conserved binding site for anionic calixarenes implicates this region of PAF in membrane binding, which is a prerequisite for antifungal activity.

PubMed: 30867921
DOI: 10.1107/S2052252519000411

Experimental method

X-RAY DIFFRACTION (1.33 Å)