Proteopedia entry: Coiled‐coil structure of keratins

Epidermolysis bullosa simplex–generalized severe type due to keratin 5 p.Glu477Lys mutation: Genotype‐phenotype correlation and in silico modeling analysis

“…In order to provide insight into the consequences of this change, we performed in silico modeling of the K5‐K14 coil 2B complex using CCBuilder and rendered with Pymol (Schrodinger, LLC, New York, NY; Figure ). The predicted surface model based on the van der Waals radius of atoms of the coiled‐coil structure of 2B domains of K5 and K14 (Figure A) is close to the published model based on crystallographic data . In silico model of the K5 p.Glu477Lys mutation predicts a local conformational change of arginine (Arg) 471, predicted to form a hydrogen bond with tyrosine (Tyr) 415 of K14 and an electrostatic interaction with Glu411 of K14 .…”

“…Glu477 is thus predicted to interact with Leu419 located at the “a” position of K14, but the “d” positions in K5 are usually occupied by hydrophobic residues (such as leucine and alanine), and no glutamic acid residue is present in any “d” position in the heptads of K5 or K14 2B domains . Moreover, glutamic acid is a charged residue mainly found at position “g” (and at a lesser frequency at positions “b,” “c,” and “e”) . In fact, radiograph crystallography data indicate that K5‐K14 features more asymmetric salt bridges (between “g” and “e” positions) and fewer hydrophobic interaction clusters than homodimeric intermediate filaments.…”

Draft Genome Sequence of Chryseobacterium sp. Strain P1-3, a Keratinolytic Bacterium Isolated from Poultry Waste

“…The insoluble protein is tightly packed in an α-helix structure (α-keratin) or β-sheet structure (β-keratin) into a supercoiled polypeptide chain with cysteine bridges ( 2 ). Keratin shows resistance to proteolysis due not only to the disulfide bonds, but also to the structurally limited interior space with hydrophobic interactions between nonpolar residues ( 3 ). The proteolytic resistance of keratin has been considered to be a critical factor disturbing the process of keratin waste treatment ( 4 ).…”

Complete genome sequence of a keratin-degrading bacterium Chryseobacterium gallinarum strain DSM 27622T isolated from chicken

“…Keratin is the main constituent of bird's feather, animal hairs, nails, wool and present abundantly in the skin tissues of vertebrates (Gradišar et al, 2005). Keratins are highly resistant to proteolytic enzymes due to the presence of numerous disulfide bonds as well as structurally limited interior space for hydrophobic interactions between nonpolar residues (Hanukoglu and Ezra, 2014). Such structural rigidity is a main limiting factor for the use of keratin-based waste treatment (Korniłłowicz-Kowalska and Bohacz, 2011).…”