Acquisition of ordered conformation by the N-terminal domain of the human small proline rich 2 protein.
The cornified cell envelope (CE) is a crucial structure for barrier function in terminally differentiated dead stratified squamous epithelia. It is assembled by transglutaminase enzymes (TGases) that cross-link several proteins such as loricrin and the small proline rich (SPR) proteins. Human SPR2 protein is cross-linked with widely differing efficiencies by TGases 1, 2, and 3 using exclusively residues in the N- and C-terminal domains. In order to understand if the absence of the cross-linking catalyzed by TGases in the central domain is due to the conformation adopted, we have investigated the structural properties in solution of three peptides that correspond to the N-terminal domain, to three repeats of the central domain, and to the C-terminal domain. Together, the NMR and CD data strongly indicate the presence of a highly flexible non alpha-helix, non beta-sheet structure in SPR2. Thus, SPR2 appears to function as a flexible cross-bridging protein to provide tensile strength or rigidity to the CE of the stratified squamous epithelia in which it is expressed.
Candi
E
E
Istituto Dermopatico dell'Immacolata, University Tor Vergata, Rome, Italy.
Melino
G
G
Sette
M
M
Oddi
S
S
Guerrieri
P
P
Paci
M
M
D000595:Amino Acid Sequence; D002942:Circular Dichroism; D017124:Conserved Sequence; D055233:Cornified Envelope Proline-Rich Proteins; D006801:Humans; D007381:Intermediate Filament Proteins / Q000737:chemistry* / Q000187:drug effects; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D010446:Peptide Fragments / Q000737:chemistry* / Q000187:drug effects; D018583:Pliability; D017433:Protein Structure, Secondary; D020449:Repetitive Sequences, Amino Acid; D014270:Trifluoroethanol / Q000494:pharmacology
D055233:Cornified Envelope Proline-Rich Proteins; D007381:Intermediate Filament Proteins; D010446:Peptide Fragments; C491986:SPRR2B protein, human; C491987:SPRR2D protein, human; D014270:Trifluoroethanol