Tags

Type your tag names separated by a space and hit enter

Comparative in vitro analyses of recombinant maize starch synthases SSI, SSIIa, and SSIII reveal direct regulatory interactions and thermosensitivity.
Arch Biochem Biophys. 2016 Apr 15; 596:63-72.AB

Abstract

Starch synthases SSI, SSII, and SSIII function in assembling the amylopectin component of starch, but their specific roles and means of coordination are not fully understood. Genetic analyses indicate regulatory interactions among SS classes, and physical interactions among them are known. The N terminal extension of cereal SSIII, comprising up to 1200 residues beyond the catalytic domain, is responsible at least in part for these interactions. Recombinant maize SSI, SSIIa, and full-length or truncated SSIII, were tested for functional interactions regarding enzymatic activity. Amino-terminal truncated SSIII exhibited reduced activity compared to full-length enzyme, and addition of the N terminus to the truncated protein stimulated catalytic activity. SSIII and SSI displayed a negative interaction that reduced total activity in a reconstituted system. These data demonstrate that SSIII is both a catalytic and regulatory factor. SSIII activity was reduced by approximately 50% after brief incubation at 45 °C, suggesting a role in reduced starch accumulation during growth in high temperatures. Buffer effects were tested to address a current debate regarding the SS mechanism. Glucan stimulated the SSIIa and SSIII reaction rate regardless of the buffer system, supporting the accepted mechanism in which glucosyl units are added to exogenous primer substrates.

Links

Publisher Full Text (DOI)

Authors+Show Affiliations

Huang B
Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50011, USA.
Keeling PL
Center for Biorenewable Chemicals, 1140K Biorenewables Research Laboratory, Iowa State University, Ames, IA 50011, USA.
Hennen-Bierwagen TA
Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50011, USA.
Myers AM
Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50011, USA. Electronic address: ammyers@iastate.edu.

MeSH

AmylopectinCatalysisEnzyme StabilityHot TemperaturePlant ProteinsProtein DomainsRecombinant ProteinsStarch SynthaseZea mays

Pub Type(s)

Comparative Study
Journal Article

Language

eng

PubMed ID

26940263

Citation

Huang, Binquan, et al. "Comparative in Vitro Analyses of Recombinant Maize Starch Synthases SSI, SSIIa, and SSIII Reveal Direct Regulatory Interactions and Thermosensitivity." Archives of Biochemistry and Biophysics, vol. 596, 2016, pp. 63-72.
Huang B, Keeling PL, Hennen-Bierwagen TA, et al. Comparative in vitro analyses of recombinant maize starch synthases SSI, SSIIa, and SSIII reveal direct regulatory interactions and thermosensitivity. Arch Biochem Biophys. 2016;596:63-72.
Huang, B., Keeling, P. L., Hennen-Bierwagen, T. A., & Myers, A. M. (2016). Comparative in vitro analyses of recombinant maize starch synthases SSI, SSIIa, and SSIII reveal direct regulatory interactions and thermosensitivity. Archives of Biochemistry and Biophysics, 596, 63-72. https://doi.org/10.1016/j.abb.2016.02.032
Huang B, et al. Comparative in Vitro Analyses of Recombinant Maize Starch Synthases SSI, SSIIa, and SSIII Reveal Direct Regulatory Interactions and Thermosensitivity. Arch Biochem Biophys. 2016 Apr 15;596:63-72. PubMed PMID: 26940263.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Comparative in vitro analyses of recombinant maize starch synthases SSI, SSIIa, and SSIII reveal direct regulatory interactions and thermosensitivity. AU - Huang,Binquan, AU - Keeling,Peter L, AU - Hennen-Bierwagen,Tracie A, AU - Myers,Alan M, Y1 - 2016/03/03/ PY - 2015/12/08/received PY - 2016/02/06/revised PY - 2016/02/28/accepted PY - 2016/3/5/entrez PY - 2016/3/5/pubmed PY - 2017/4/30/medline KW - Endosperm KW - Maize KW - Starch structure KW - Starch synthase KW - Thermosensitivity SP - 63 EP - 72 JF - Archives of biochemistry and biophysics JO - Arch Biochem Biophys VL - 596 N2 - Starch synthases SSI, SSII, and SSIII function in assembling the amylopectin component of starch, but their specific roles and means of coordination are not fully understood. Genetic analyses indicate regulatory interactions among SS classes, and physical interactions among them are known. The N terminal extension of cereal SSIII, comprising up to 1200 residues beyond the catalytic domain, is responsible at least in part for these interactions. Recombinant maize SSI, SSIIa, and full-length or truncated SSIII, were tested for functional interactions regarding enzymatic activity. Amino-terminal truncated SSIII exhibited reduced activity compared to full-length enzyme, and addition of the N terminus to the truncated protein stimulated catalytic activity. SSIII and SSI displayed a negative interaction that reduced total activity in a reconstituted system. These data demonstrate that SSIII is both a catalytic and regulatory factor. SSIII activity was reduced by approximately 50% after brief incubation at 45 °C, suggesting a role in reduced starch accumulation during growth in high temperatures. Buffer effects were tested to address a current debate regarding the SS mechanism. Glucan stimulated the SSIIa and SSIII reaction rate regardless of the buffer system, supporting the accepted mechanism in which glucosyl units are added to exogenous primer substrates. SN - 1096-0384 UR - https://www.unboundmedicine.com/medline/citation/26940263/Comparative_in_vitro_analyses_of_recombinant_maize_starch_synthases_SSI_SSIIa_and_SSIII_reveal_direct_regulatory_interactions_and_thermosensitivity_ DB - PRIME DP - Unbound Medicine ER -