title: Three-dimensional structure of fungal proteinase K reveals similarity to bacterial subtilisin.
abstract: The three-dimensional structure of the fungal serine protease proteinase K has been determined at 3.3 A resolution by single crystal X-ray diffraction analysis. The enzyme crystallizes in the tetragonal space group P4(3)2(1)2 with cell constants a = b = 68.3 A, c = 108.5 A. The asymmetric unit consists of one monomer of 27 000 daltons mol. wt., approximately 50% higher than the so far assumed value of 18 500 daltons. The main chain fold of proteinase K shows a high degree of tertiary homology with the corresponding bacterial subtilisin BPN'. Proteinase K is the second enzyme in this family of serine proteases to be studied by X-ray diffraction, thus confirming the existence of two unrelated families of serine proteases in pro-and eukaryotes.
mesh_terms: D001419:Bacteria / Q000201:enzymology*; D019286:Endopeptidase K; D010450:Endopeptidases / Q000302:isolation & purification; D003904:Mitosporic Fungi / Q000201:enzymology*; D008958:Models, Molecular; D011487:Protein Conformation; D013329:Structure-Activity Relationship; D013381:Subtilisins; D014961:X-Ray Diffraction
chemical_list: D010450:Endopeptidases; D013381:Subtilisins; D019286:Endopeptidase K