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Crystal structure of the heterocomplex between coil 2B domains of wild-type keratin 1 (KRT1) and keratin 10 (KRT10) containing mutation Cys401Ala
Structural highlights
DiseaseK2C1_HUMAN Epidermolytic palmoplantar keratoderma;Ichthyosis hystrix of Curth-Macklin;Annular epidermolytic ichthyosis;Epidermolytic ichthyosis;Keratosis palmoplantaris striata. The disease is caused by mutations affecting the gene represented in this entry. The disease is caused by mutations affecting the gene represented in this entry. The disease is caused by mutations affecting the gene represented in this entry. The disease is caused by mutations affecting the gene represented in this entry. The disease is caused by mutations affecting the gene represented in this entry. FunctionK2C1_HUMAN May regulate the activity of kinases such as PKC and SRC via binding to integrin beta-1 (ITB1) and the receptor of activated protein C kinase 1 (RACK1). In complex with C1QBP is a high affinity receptor for kininogen-1/HMWK.[1] [2] Publication Abstract from PubMedWe previously determined the crystal structure of the wild-type keratin 1/10 helix 2B heterodimer at 3.3 A resolution. We proposed that the resolution of the diffraction data was limited due to the crystal packing effect from keratin 10 (K10) residue Cys401. Cys401(K10) formed a disulfide-linkage with Cys401 from another K1/10 heterodimer, creating an "X-shaped" structure and a loose crystal packing arrangement. We hypothesized that mutation of Cys401(K10) to alanine would eliminate the disulfide-linkage and improve crystal packing thereby increasing resolution of diffraction and enabling a more accurate side chain electron density map. Indeed, when a K10 Cys401Ala 2B mutant was paired with its native keratin 1 (K1) 2B heterodimer partner its x-ray crystal structure was determined at 2.07 A resolution; the structure does not contain a disulfide linkage. Superposition of the K1/K10(Cys401Ala) 2B structure onto the wild-type K1/10 2B heterodimer structure had a root-mean-square-deviation of 1.88 A; the variability in the atomic positions reflects the dynamic motion expected in this filamentous coiled-coil complex. The electrostatic, hydrophobic, and contour features of the molecular surface are similar to the lower resolution wild-type structure. We postulated that elimination of the disulfide linkage in the K1/K10(Cys401Ala) 2B structure could allow for the 2B heterodimers to bind/pack in the A22 tetramer configuration associated with mature keratin intermediate filament assembly. Analysis of the crystal packing revealed a half-staggered anti-parallel tetrameric complex of 2B heterodimers; however, their register is not consistent with models of the A22 mode of tetrameric alignment or prior biochemical cross-linking studies. Crystal Structure of Keratin 1/10(C401A) 2B Heterodimer Demonstrates a Proclivity for the C-Terminus of Helix 2B to Form Higher Order Molecular Contacts.,Lomakin IB, Hinbest AJ, Ho M, Eldirany SA, Bunick CG Yale J Biol Med. 2020 Mar 27;93(1):3-17. eCollection 2020 Mar. PMID:32226330[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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