+ Site Statistics
References:
54,258,434
Abstracts:
29,560,870
PMIDs:
28,072,757
+ Search Articles
+ PDF Full Text Service
How our service works
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ Translate
+ Recently Requested

Homodimers of mutant tryptophan synthase alpha-subunits in Escherichia coli



Homodimers of mutant tryptophan synthase alpha-subunits in Escherichia coli



Biochemical and Biophysical Research Communications 289(2): 568-572



Tryptophan synthase alpha-subunit from Escherichia coli functionally exists as a heterotetramer of alpha(2)beta(2) with beta-subunit. While wild-type and mutant (F139W, T24M/F139W, and T24L/F139W) alpha-subunits were expressed as a monomer from recombinant plasmids in Escherichia coli, T24A/F139W, T24S/F139W, and T24K/F139W mutant alpha-subunits were abnormally expressed as soluble homodimers in addition to monomers. Monomers of dimer-forming mutant alpha-subunits retain high affinity to beta-subunit, high activity in stimulating catalytic activities of beta-subunit, and nearly intact content of secondary structure, indicating that the global structures of these monomers are identical to that of F139W alpha-subunit. However, fluorescence spectra of Trp139 and ANS binding indicate that significant perturbations occur in the mutant proteins. Interestingly, these defective properties of monomers caused by residue replacement were partially repaired by the dimer formation. As a result, it is suggested that dimers may be formed by domain or loop swapping, and that residue 24 may play important role in maintaining on-pathway of alpha-subunit folding.

Please choose payment method:






(PDF emailed within 0-6 h: $19.90)

Accession: 010759025

Download citation: RISBibTeXText

PMID: 11716512

DOI: 10.1006/bbrc.2001.6022


Related references

Enzymatic properties of mutant Escherichia coli tryptophan synthase alpha-subunits. Journal of Biological Chemistry 266(30): 20205-20212, 1991

Thermal stabilities of mutant Escherichia coli tryptophan synthase alpha subunits. Archives of Biochemistry and Biophysics 292(1): 34-41, 1992

Structure and folding of mutant escherichia coli tryptophan synthase alpha subunits. Journal of Cellular Biochemistry Supplement (9 PART B): 95, 1985

Relative activities and stabilities of mutant Escherichia coli tryptophan synthase alpha subunits. Journal of Bacteriology 173(6): 1886-1893, 1991

Fluorescence and folding properties of Tyr mutant tryptophan synthase alpha-subunits from Escherichia coli. Biochemical and Biophysical Research Communications 300(1): 29-35, 2002

Substrate interactions with the alpha-subunit of the Escherichia coli tryptophan synthase. A study of the activity of mutant alpha-subunits. Archives of Biochemistry and Biophysics 181(2): 428-437, 1977

Crystallization and X-ray crystallographic studies of wild-type and mutant tryptophan synthase alpha-subunits from Escherichia coli. Molecules and Cells 19(2): 219-222, 2005

Enzymatic properties of mutant escherichia coli tryptophan synthase alpha subunits obtained from in vitro mutagenesis of the trp a gene. FASEB Journal 4(7): A1760, 1990

In vitro mutagenesis and overexpression of the Escherichia coli trpA gene and the partial characterization of the resultant tryptophan synthase mutant alpha-subunits. Journal of Biological Chemistry 261(35): 16604-16615, 1986

Unfolding properties of tryptophan-containing alpha-subunits of the Escherichia coli tryptophan synthase. Journal of Biological Chemistry 270(47): 28177-28182, 1995

Tryptophan-containing alpha-subunits of the Escherichia coli tryptophan synthase. Enzymatic and urea stability properties. Journal of Biological Chemistry 270(30): 17712-5, 1995

Enzymatic properties of mutant Escherichia coli tryptophan synthase a-subunits. The Journal of Biological Chemistry 266: 205-12, 1991

Subunit interaction in tryptophan synthase ec 4.2.1.20 of escherichia coli calorimetric studies on association of alpha subunits and beta 2 subunits. Biochemistry 18(10): 1979-1984, 1979

Relative activities and stabilities of mutant Escherichia coli tryptophan synthase a subunits. Journal of Bacteriology 173(6): 86-93, 1991