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Article
Starch‐binding domain shuffling in Aspergillus niger glucoamylase
Protein Engineering Design and Selection
  • Catherine A.G. Cornett, Iowa State University
  • Tsuei-Yun Fang, Iowa State University
  • Peter J. Reilly, Iowa State University
  • Clark Ford, Iowa State University
Document Type
Article
Publication Date
1-1-2003
DOI
10.1093/protein/gzg066
Abstract

Aspergillus niger glucoamylase (GA) consists mainly of two forms, GAI [from the N‐terminus, catalytic domain + linker + starch‐binding domain (SBD)] and GAII (catalytic domain + linker). These domains were shuffled to make RGAI (SBD + linker + catalytic domain), RGAIΔL (SBD + catalytic domain) and RGAII (linker + catalytic domain), with domains defined by function rather than by tertiary structure. In addition, Paenibacillus macerans cyclomaltodextrin glucanotransferase SBD replaced the closely related A.niger GA SBD to give GAE. Soluble starch hydrolysis rates decreased as RGAII ≈ GAII ≈ GAI > RGAIΔL ≈ RGAI ≈ GAE. Insoluble starch hydrolysis rates were GAI > RGAIΔL > RGAI >> GAE ≈ RGAII > GAII, while insoluble starch‐binding capacities were GAI > RGAI > RGAIΔL > RGAII > GAII > GAE. These results indicate that: (i) moving the SBD to the N‐terminus or replacing the native SBD somewhat affects soluble starch hydrolysis; (ii) SBD location significantly affects insoluble starch binding and hydrolysis; (iii) insoluble starch hydrolysis is imperfectly correlated with its binding by the SBD; and (iv) placing the P.maceranscyclomaltodextrin glucanotransferase SBD at the end of a linker, instead of closely associated with the rest of the enzyme, severely reduces its ability to bind and hydrolyze insoluble starch.

Comments

This is a post-print of an article from Protein Engineering Design & Selection, 16, no. 7 (2003): 521–529, doi: 10.1093/protein/gzg066.

Copyright Owner
Oxford University Press
Language
en
File Format
application/pdf
Citation Information
Catherine A.G. Cornett, Tsuei-Yun Fang, Peter J. Reilly and Clark Ford. "Starch‐binding domain shuffling in Aspergillus niger glucoamylase" Protein Engineering Design and Selection Vol. 16 Iss. 7 (2003) p. 521 - 529
Available at: http://works.bepress.com/peter_reilly/22/