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Identification of succinic semialdehyde reductases from Geobacter: expression, purification, crystallization, preliminary functional, and crystallographic analysis

Journal Article · · Acta Bioch. Bioph. Sin.
DOI:https://doi.org/10.1093/abbs/gmr097· OSTI ID:1031933
Succinic semialdehyde reductase (SSAR) is an important enzyme involved in {gamma}-aminobutyrate (GABA) metabolism. By converting succinic semialdehyde (SSA) to {gamma}-hydroxybutyrate (GHB), the SSAR facilitates an alternative pathway for GABA degradation. In this study, we identified SSARs from Geobacter sulfurreducens and Geobacter metallireducens (GsSSAR and GmSSAR, respectively). The enzymes were over-expressed in Escherichia coli and purified to near homogeneity. Both GsSSAR and GmSSAR showed the activity of reducing SSA using nicotinamide adenine dinucleotide phosphate as a co-factor. The oligomeric sizes of GsSSAR and GmSSAR, as determined by analytical size exclusion chromatography, suggest that the enzymes presumably exist as tetramers in solution. The recombinant GsSSAR and GmSSAR crystallized in the presence of NADP{sup +}, and the resulting crystals diffracted to 1.89 {angstrom} (GsSSAR) and 2.25 {angstrom} (GmSSAR) resolution. The GsSSAR and GmSSAR crystals belong to the space groups P2{sub 1}22{sub 1} (a = 99.61 {angstrom}, b = 147.49 {angstrom}, c = 182.47 {angstrom}) and P1 (a = 75.97 {angstrom}, b = 79.14 {angstrom}, c = 95.47 {angstrom}, {alpha} = 82.15{sup o}, {beta} = 88.80{sup o}, {gamma} = 87.66{sup o}), respectively. Preliminary crystallographic data analysis suggests the presence of eight protein monomers in the asymmetric units for both GsSSAR and GmSSAR.
Research Organization:
Advanced Photon Source (APS), Argonne National Laboratory (ANL), Argonne, IL (US)
Sponsoring Organization:
USDOE Office of Science (SC)
OSTI ID:
1031933
Journal Information:
Acta Bioch. Bioph. Sin., Journal Name: Acta Bioch. Bioph. Sin. Journal Issue: (12) ; 2011 Vol. 43; ISSN 1672-9145
Country of Publication:
United States
Language:
ENGLISH