Glu31, Asp142 and Asp171 of Aspergillus oryzae cutinase CutL1 are required for both interaction with hydrophobin RolA and consequent stimulation of polyester-degradation.

Kimihide Muragaki1, Kenji Uehara1, Toru Takahashi2,3, Youhei Yamagata3 and Keietsu Abe1,3*

Author address: 

1Grad. Sch. Agric. Sci., Tohoku Univ., Japan, 2NRIB, Japan, 3NICHe, Tohoku Univ., Japan


Hydrophobins are amphipathic proteins, and are ubiquitous among filamentous fungi. When the industrial fungus Aspergillus oryzae is cultivated in a submerged medium containing a biodegradable polyester polybutylene succinate-coadipate (PBSA), cutinase CutL1 and hydrophobin RolA are simultaneously secreted into the medium. RolA attached to the surface of PBSA particles specifically recruits CutL1, resulting in stimulation of PBSA hydrolysis1). In our previous study, we studied amino acid residues involved in the RolA-CutL1 interaction by means of chemical modification and site-directed mutagenesis of RolA and CutL1. As a result, we found that His32 and Lys34 of RolA and Glu31, Asp142, Asp171 of CutL1 are involved in the RolA-CutL1 interaction. In the present study, to quantitatively elucidate the role of the three acidic amino acid residues of CutL1 in the RolA-CutL1 interaction, we characterized the interaction between CutL1 variants of the three residues and wild type RolA by using Quartz Crystal Microbalance (QCM). The QCM analysis revealed that replacement of the three acidic amino acid residues of CutL1 to serine caused increases in KD values for interaction with RolA. In conclusion, Glu31, Asp142 and Asp171 of CutL1 are critically required for the RolA-CutL1 interaction by multivalent effect. 1) Takahashi et al. Mol Microbiol. 57:1780 (2005)

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Full conference title: 

26th Fungal Genetics Conference
    • Fungal Genetics Conference 26th (2005)