Solution structure and assembly of β-amylase2 from Arabidopsis thaliana

AbstractStarch is a key energy storage molecule in plants that requires controlled synthesis and breakdown for effective plant growth. β-amylases (BAMs) hydrolyze starch into maltose to help meet the metabolic needs of the plant. In the model plant, Arabidopsis thaliana, there are nine BAMs which have apparently distinct functional and domain structures, although the functions of only a few of the BAMs are known and there are no 3-D structures of BAMs from this organism. Recently, AtBAM2 was proposed to form a tetramer based on chromatography and activity assays of mutants, however there was no direct observation of this tetramer. We collected small-angle X-ray scattering data on AtBAM2 and N-terminal mutants to describe the structure and assembly of the tetramer. Comparison of the scattering of the AtBAM2 tetramer to data collected using the sweet potato (Ipomoea batatas) BAM5, which is also reported to form a tetramer, showed there were differences in the overall assembly. Analysis of N-terminal truncations of AtBAM2 identified a loop sequence found only in BAM2 orthologs that appears to be critical for AtBAM2 tetramer assembly as well as activity.

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Solution structure and assembly of β-amylase 2 from Arabidopsis thaliana

Acta Crystallographica Section D Structural Biology ◽

10.1107/s2059798320002016 ◽

2020 ◽

Vol 76 (4) ◽

pp. 357-365 ◽

Cited By ~ 1

Author(s):

Nithesh P. Chandrasekharan ◽

Claire M. Ravenburg ◽

Ian R. Roy ◽

Jonathan D. Monroe ◽

Christopher E. Berndsen

Keyword(s):

Arabidopsis Thaliana ◽

Ipomoea Batatas ◽

Solution Structure ◽

Scattering Data ◽

Controlled Synthesis ◽

X Ray ◽

Domain Structures ◽

X Ray Scattering ◽

Loop Sequence ◽

Assembly Analysis

Starch is a key energy-storage molecule in plants that requires controlled synthesis and breakdown for effective plant growth. β-Amylases (BAMs) hydrolyze starch into maltose to help to meet the metabolic needs of the plant. In the model plant Arabidopsis thaliana there are nine BAMs, which have apparently distinct functional and domain structures, although the functions of only a few of the BAMs are known and there are no 3D structures of BAMs from this organism. Recently, AtBAM2 was proposed to form a tetramer based on chromatography and activity assays of mutants; however, there was no direct observation of this tetramer. Here, small-angle X-ray scattering data were collected from AtBAM2 and its N-terminal truncations to describe the structure and assembly of the tetramer. Comparison of the scattering of the AtBAM2 tetramer with data collected from sweet potato (Ipomoea batatas) BAM5, which is also reported to form a tetramer, showed there were differences in the overall assembly. Analysis of the N-terminal truncations of AtBAM2 identified a loop sequence found only in BAM2 orthologs that appears to be critical for AtBAM2 tetramer assembly as well as for activity.

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The solution structure of the complement deregulator FHR5 reveals a compact dimer and provides new insights into CFHR5 nephropathy

Journal of Biological Chemistry ◽

10.1074/jbc.ra120.015132 ◽

2020 ◽

Vol 295 (48) ◽

pp. 16342-16358

Author(s):

Nilufar Kadkhodayi-Kholghi ◽

Jayesh S. Bhatt ◽

Jayesh Gor ◽

Lindsay C. McDermott ◽

Daniel P. Gale ◽

...

Keyword(s):

Solution Structure ◽

Factor H ◽

Scattering Data ◽

Radius Of Gyration ◽

Domain Pair ◽

Complement Factor ◽

X Ray ◽

X Ray Scattering ◽

Complement Regulator ◽

Ray Scattering

The human complement Factor H–related 5 protein (FHR5) antagonizes the main circulating complement regulator Factor H, resulting in the deregulation of complement activation. FHR5 normally contains nine short complement regulator (SCR) domains, but a FHR5 mutant has been identified with a duplicated N-terminal SCR-1/2 domain pair that causes CFHR5 nephropathy. To understand how this duplication causes disease, we characterized the solution structure of native FHR5 by analytical ultracentrifugation and small-angle X-ray scattering. Sedimentation velocity and X-ray scattering indicated that FHR5 was dimeric, with a radius of gyration (Rg) of 5.5 ± 0.2 nm and a maximum protein length of 20 nm for its 18 domains. This result indicated that FHR5 was even more compact than the main regulator Factor H, which showed an overall length of 26–29 nm for its 20 SCR domains. Atomistic modeling for FHR5 generated a library of 250,000 physically realistic trial arrangements of SCR domains for scattering curve fits. Only compact domain structures in this library fit well to the scattering data, and these structures readily accommodated the extra SCR-1/2 domain pair present in CFHR5 nephropathy. This model indicated that mutant FHR5 can form oligomers that possess additional binding sites for C3b in FHR5. We conclude that the deregulation of complement regulation by the FHR5 mutant can be rationalized by the enhanced binding of FHR5 oligomers to C3b deposited on host cell surfaces. Our FHR5 structures thus explained key features of the mechanism and pathology of CFHR5 nephropathy.

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Faculty Opinions recommendation of Solution structure of the 128 kDa enzyme I dimer from Escherichia coli and its 146 kDa complex with HPr using residual dipolar couplings and small- and wide-angle X-ray scattering.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.12482956.13700054 ◽

2011 ◽

Author(s):

Vitali Tugarinov

Keyword(s):

Escherichia Coli ◽

Solution Structure ◽

Residual Dipolar Couplings ◽

Dipolar Couplings ◽

Wide Angle ◽

X Ray ◽

X Ray Scattering ◽

Enzyme I ◽

Ray Scattering

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Structure of the amorphous titania precursor phase of N-doped photocatalysts

RSC Advances ◽

10.1039/d0ra08886b ◽

2021 ◽

Vol 11 (15) ◽

pp. 8619-8627

Author(s):

I. E. Grey ◽

P. Bordet ◽

N. C. Wilson

Keyword(s):

Thermal Analyses ◽

Real Space ◽

Ammonia Solution ◽

Scattering Data ◽

X Ray ◽

X Ray Scattering ◽

Amorphous Titania ◽

Precursor Phase ◽

Titania Precursor ◽

Titanyl Sulphate

Amorphous titania samples prepared by ammonia solution neutralization of titanyl sulphate have been characterized by chemical and thermal analyses, and with reciprocal-space and real-space fitting of wide-angle synchrotron X-ray scattering data.

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