Poly(3-hydroxybutyrate) depolymerases bind to their substrate by a C-terminal located substrate binding site.
Binding of (i) purified wild-type poly(3-hydroxybutyrate) (PHB) depolymerase PhaZ4 of Pseudomonas lemoignei, (ii) a purified truncated form of PhaZ4, which lacked 55 C-terminal amino acids and (iii) commercial lactate dehydrogenase to aqueous suspensions of PHB, chitin or cellulose was studied. Only the wild-type PHB depolymerase was specifically able to bind to PHB granules. No other combination of protein and polymeric substrate resulted in polymer-bound protein. Similar results were obtained for other PHB depolymerases. We concluded that the C-terminal amino acids of PHB depolymerases represent a PHB-specific binding domain or at least an essential part of it.
Behrends
A
A
Institut für Mikrobiologie, Georg-August-Universität Göttingen, Germany.
Klingbeil
B
B
Jendrossek
D
D
D000595:Amino Acid Sequence; D001665:Binding Sites; D002265:Carboxylic Ester Hydrolases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D004926:Escherichia coli; D008969:Molecular Sequence Data; D016296:Mutagenesis; D011549:Pseudomonas / Q000201:enzymology / Q000235:genetics; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
D011994:Recombinant Proteins; D002265:Carboxylic Ester Hydrolases; C022417:poly-beta-hydroxybutyrate depolymerase