Guanidine hydrochloride-induced denaturation and thermal denaturation of three kinds of tryptophan synthase alpha subunit have been compared by circular dichroism measurements. The three alpha subunits are from Escherichia coli, Salmonella typhimurium, and an interspecies hybrid in which the C-terminal domain comes from E. coli (alpha-2 domain) and the N-terminal domain comes from S. typhimurium (alpha-1 domain). Analysis of denaturation by guanidine hydrochloride at 25 degrees C showed that the alpha-2 domain of S. typhimurium was more stable than the alpha-2 domain of E. coli, but the alpha-1 domain of S. typhimurium was less stable than the alpha-1 domain of the E. coli protein; overall, the hybrid protein was slightly less stable than the two original proteins. It is concluded that the stability to guanidine hydrochloride denaturation of each of the domains of the interspecies hybrid is similar to the stability of the domain of the species from which it originated. The E. coli protein was more stable to thermal denaturation than the other proteins near the denaturation temperature, but the order of their thermal stability was reversed at 25 degrees C and coincided with that obtained from guanidine hydrochloride-induced denaturation. Study holds ProTherm entries: 7331, 7332, 7333 Extra Details: additive : EDTA(0.1 mM), alpha subunit; N-terminal domain; thermal denaturation;,denaturation temperature
Submitter: Connie Wang
Submission Date: April 24, 2018, 8:33 p.m.
|Number of data points||3|
|Proteins||Tryptophan synthase alpha chain ; Tryptophan synthase alpha chain ; Tryptophan synthase alpha chain ; Tryptophan synthase alpha chain|
|Assays/Quantities/Protocols||Experimental Assay: dG_H2O|
|Libraries||Mutations for sequence A:MERYENLFAQLNDRREGAFVPFVTLGDPGIEQSLKIIDTLIDAGADALELGVPFSDPLADGPTIQNANLRAFAAGVTPAQCFEMLALIREKHPTIPIGLLMYANLVFNNGIDAFYARCEQVGVDSVLVADVPVEESAPFRQAALRHNIAPIFICPPNADDDLLRQVASYGRGYTYLLSRSGVTGAENRGALPLHHLIEKLKEYHAAPALQGFGISSPEQVSAAVRAGAAGAISGSAIVKIIEKNLASPKQMLAELRSFVSAMKAASRA/B:TTLLNPYFGEFGGMYVPQILMPALNQLEEAFVRAQKDPEFQAQFADLLKNYAGRPTALTKCQNITAGTRTTLYLKREDLLHGGAHKTNQVLGQALLAKRMGKSEIIAETGAGQHGVASALASALLGLKCRIYMGAKDVERQSPNVFRMRLMGAEVIPVHSGSATLKDACNEALRDWSGSYETAHYMLGTAAGPHPYPTIVREFQRMIGEETKAQILDKEGRLPDAVIACVGGGSNAIGMFADFINDTSVGLIGVEPGGHGIETGEHGAPLKHGRVGIYFGMKAPMMQTADGQIEESYSISAGLDFPSVGPQHAYLNSIGRADYVSITDDEALEAFKTLCRHEGIIPALESSHALAHALKMMREQPEKEQLLVVNLSGRGDKDIFTVHDILKARGEI ; Mutations for sequence MERYESLFAQLKERKEGAFVPFVTLGDPGIEQSLKIIDTLIEAGADALELGIPFSDPLADGPTIQNATLRAFAAGVTPAQCFEMLALIRQKHPTIPIGLLMYANLVFNKGIDEFYAQCEKVGVDSVLVADVPVEESAPFRQAALRHNVAPIFICPPNADDDLLRQIASYGRGYTYLLSRAGVTGAENRAALPLNHLVAKLKEYNAAPPLQGFGISAPDQVKAAIDAGAAGAISGSAIVKIIEQHINEPEKMLAALKVFVQPMKAATRS|