title: Novel hydrophobic surface binding protein, HsbA, produced by Aspergillus oryzae.
abstract: Hydrophobic surface binding protein A (HsbA) is a secreted protein (14.5 kDa) isolated from the culture broth of Aspergillus oryzae RIB40 grown in a medium containing polybutylene succinate-co-adipate (PBSA) as a sole carbon source. We purified HsbA from the culture broth and determined its N-terminal amino acid sequence. We found a DNA sequence encoding a protein whose N terminus matched that of purified HsbA in the A. ozyzae genomic sequence. We cloned the hsbA genomic DNA and cDNA from A. oryzae and constructed a recombinant A. oryzae strain highly expressing hsbA. Orthologues of HsbA were present in animal pathogenic and entomopathogenic fungi. Heterologously synthesized HsbA was purified and biochemically characterized. Although the HsbA amino acid sequence suggests that HsbA may be hydrophilic, HsbA adsorbed to hydrophobic PBSA surfaces in the presence of NaCl or CaCl(2). When HsbA was adsorbed on the hydrophobic PBSA surfaces, it promoted PBSA degradation via the CutL1 polyesterase. CutL1 interacts directly with HsbA attached to the hydrophobic QCM electrode surface. These results suggest that when HsbA is adsorbed onto the PBSA surface, it recruits CutL1, and that when CutL1 is accumulated on the PBSA surface, it stimulates PBSA degradation. We previously reported that when the A. oryzae hydrophobin RolA is bound to PBSA surfaces, it too specifically recruits CutL1. Since HsbA is not a hydrophobin, A. oryzae may use several types of proteins to recruit lytic enzymes to the surface of hydrophobic solid materials and promote their degradation.
authors.affiliation: Laboratory of Molecular Enzymology, Department of Molecular and Cell Biology, Graduate School of Agricultural Science, Tohoku University, 1-1 Amamiya, Tsutsumi-dori, Aobaku, Sendai 981-8555, Japan.
authors.forename: Shinsaku
authors.initials: S
authors.lastname: Ohtaki
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Maeda
authors.forename: Toru
authors.initials: T
authors.lastname: Takahashi
authors.forename: Youhei
authors.initials: Y
authors.lastname: Yamagata
authors.forename: Fumihiko
authors.initials: F
authors.lastname: Hasegawa
authors.forename: Katsuya
authors.initials: K
authors.lastname: Gomi
authors.forename: Tasuku
authors.initials: T
authors.lastname: Nakajima
authors.forename: Keietsu
authors.initials: K
authors.lastname: Abe
mesh_terms: D000272:Adipates / Q000378:metabolism*; D001236:Aspergillus oryzae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D001673:Biodegradation, Environmental; D001709:Biotechnology / Q000379:methods; D003470:Culture Media; D004271:DNA, Fungal / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D057927:Hydrophobic and Hydrophilic Interactions; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D010957:Plasmids / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D013386:Succinates / Q000378:metabolism*
chemical_list: D000272:Adipates; D003470:Culture Media; D004271:DNA, Fungal; D005656:Fungal Proteins; D018398:Homeodomain Proteins; D009687:Nuclear Proteins; D012097:Repressor Proteins; D013386:Succinates; C437084:poly(tetramethylene succinate-co-tetramethylene adipate)