Primary Citation of Related Structures:   6WKU
PubMed Abstract: 
Our recent work identified a genetic variant of the α345 hexamer of the collagen IV scaffold that is present in patients with glomerular basement membrane diseases, Goodpasture's disease (GP) and Alport syndrome (AS), and phenocopies AS in knock-in mice (see Companion Paper I) ...
Our recent work identified a genetic variant of the α345 hexamer of the collagen IV scaffold that is present in patients with glomerular basement membrane diseases, Goodpasture's disease (GP) and Alport syndrome (AS), and phenocopies AS in knock-in mice (see Companion Paper I). To understand the context of this "Zurich" variant, an 8-amino acid appendage, we developed a construct of the wild-type α345 hexamer using single-chain NC1 trimer technology, which allowed us to solve a crystal structure of this key connection module. The α345 hexamer structure revealed a ring of twelve chloride ions at the trimer-trimer interface, analogous to the collagen α121 hexamer, and the location of the 170 AS variants. The hexamer surface is marked by multiple pores and crevices that are potentially accessible to small molecules. Loop-crevice-loop (LCL) features constitute bioactive sites, where pathogenic pathways converge that are linked to Alport and GP diseases, and, potentially, diabetic nephropathy. In Companion Paper III, we demonstrate that these sites exhibit conformational plasticity, a dynamic property underlying assembly of bioactive sites and hexamer dysfunction. The α345 hexamer structure is a platform to decipher how variants cause AS, and how hypoepitopes can be triggered causing GP. Furthermore, the bioactive sites, along with the pores and crevices on the hexamer surface, are prospective targets for therapeutic interventions.
Related Citations: 
Collagen IV alpha 345 dysfunction in glomerular basement membrane diseases. I. Discovery of a COL4A3 variant in familial Goodpasture's and Alport diseases. Pokidysheva, E.N., Seeger, H., Pedchenko, V., Chetyrkin, S., Bergmann, C., Abrahamson, D., Cui, Z.W., Delpire, E., Fervenza, F., Fidler, A.L., Fogo, A.B., Gaspert, A., Grohmann, M., Gross, O., Haddad, G., Harris, R.C., Kashtan, C., Kitching, A.R., Lorenzen, J.M., McAdoo, S., Pusey, C.D., Segelmark, M., Simmons, A., Voziyan, P.A., Wagner, T., Wuthrich, R.P., Zhao, M.H., Boudko, S.P., Kistler, A.D., Hudson, B.G. (2021) J Biol Chem --: 100590
Collagen IV alpha 345 dysfunction in glomerular basement membrane diseases. III. A functional framework for alpha 345 hexamer assembly. Pedchenko, V., Boudko, S.P., Barber, M., Mikhailova, T., Saus, J., Harmange, J.C., Hudson, B.G. (2021) J Biol Chem --: 100592
Organizational Affiliation: 
Dept. of Medicine, Division of Nephrology and Hypertension, Vanderbilt University Medical Center, Nashville, TN, USA; Center for Matrix Biology, Vanderbilt University Medical Center, Nashville, TN, USA; Aspirnaut, Vanderbilt University Medical Center, Nashville, TN, USA; Dept. of Pathology, Microbiology and Immunology, Vanderbilt University Med. Center, Nashville, TN, USA; Dept. of Biochemistry, Center for Structural Biology, Vanderbilt University, Nashville, TN, USA; Dept. of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, USA.
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