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2c3z
From Proteopedia
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'''CRYSTAL STRUCTURE OF A TRUNCATED VARIANT OF INDOLE-3-GLYCEROL PHOSPHATE SYNTHASE FROM SULFOLOBUS SOLFATARICUS''' | '''CRYSTAL STRUCTURE OF A TRUNCATED VARIANT OF INDOLE-3-GLYCEROL PHOSPHATE SYNTHASE FROM SULFOLOBUS SOLFATARICUS''' | ||
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[[Category: Schneider, A.]] | [[Category: Schneider, A.]] | ||
[[Category: Sterner, R.]] | [[Category: Sterner, R.]] | ||
| - | [[Category: | + | [[Category: Catalytic activity,divergent evolution,tryptophan biosynthesis,lyase,decarboxylase]] |
| - | [[Category: | + | [[Category: Indole-3-glycerol phosphate synthase,protein stability]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 21:12:59 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 18:13, 3 May 2008
CRYSTAL STRUCTURE OF A TRUNCATED VARIANT OF INDOLE-3-GLYCEROL PHOSPHATE SYNTHASE FROM SULFOLOBUS SOLFATARICUS
Overview
Indole-3-glycerol phosphate synthase (IGPS) catalyzes the fifth step in the biosynthesis of tryptophan. It belongs to the large and versatile family of (betaalpha)(8)-barrel enzymes but has an unusual N-terminal extension of about 40 residues. Limited proteolysis with trypsin of IGPS from both Sulfolobus solfataricus (sIGPS) and Thermotoga maritima (tIGPS) removes about 25 N-terminal residues and one of the two extra helices contained therein. To assess the role of the extension, the N-terminally truncated variants sIGPSDelta(1-26) and tIGPSDelta(1-25) were produced recombinantly in Escherichia coli, purified, and characterized in comparison to the wild-type enzymes. Both sIGPSDelta(1-26) and tIGPSDelta(1-25) have unchanged oligomerization states and turnover numbers. In contrast, their Michaelis constants for the substrate 1-(o-carboxyphenylamino)-1-deoxyribulose 5-phosphate are increased, and their resistance toward unfolding induced by heat and guanidinium chloride is decreased. sIGPSDelta(1-26) was crystallized, and its X-ray structure was solved at 2.8 A resolution. The comparison with the known structure of sIGPS reveals small differences that account for its reduced substrate affinity and protein stability. The structure of the core of sIGPSDelta(1-26) is, however, unchanged compared to sIGPS, explaining its retained catalytic activity and consistent with the idea that it evolved from the same ancestor as the phosphoribosyl anthranilate isomerase and the alpha-subunit of tryptophan synthase. These (betaalpha)(8)-barrel enzymes catalyze the reactions preceding and following IGPS in tryptophan biosynthesis but lack an N-terminal extension.
About this Structure
2C3Z is a Single protein structure of sequence from Sulfolobus solfataricus. Full crystallographic information is available from OCA.
Reference
Role of the N-terminal extension of the (betaalpha)8-barrel enzyme indole-3-glycerol phosphate synthase for its fold, stability, and catalytic activity., Schneider B, Knochel T, Darimont B, Hennig M, Dietrich S, Babinger K, Kirschner K, Sterner R, Biochemistry. 2005 Dec 20;44(50):16405-12. PMID:16342933 Page seeded by OCA on Sat May 3 21:12:59 2008
Categories: Indole-3-glycerol-phosphate synthase | Single protein | Sulfolobus solfataricus | Darimont, B. | Dietrich, S. | Hennig, M. | Kirschner, K. | Knoechel, T. | Schneider, A. | Sterner, R. | Catalytic activity,divergent evolution,tryptophan biosynthesis,lyase,decarboxylase | Indole-3-glycerol phosphate synthase,protein stability
