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Literature summary extracted from

  • Sun, L.; Groover, O.A.; Canfield, J.M.; Warncke, K.
    Critical role of arginine 160 of the EutB protein subunit for active site structure and radical catalysis in coenzyme B12-dependent ethanolamine ammonia-lyase (2008), Biochemistry, 47, 5523-5535.
    View publication on PubMed

Cloned(Commentary)

EC Number Cloned (Comment) Organism
4.3.1.7 The plasmid containing the ethanolamine ammonia-lyase coding sequence is extracted from the Escherichia coli overexpression strain. Site-directed mutagenesis is performed on the R160 position within the eutb sequence by using the GeneTailor site-directed mutagenesis kit. Five plasmids, including the four mutations R160A, R160K, R160E, and R160I and a wild-type control, are constructed and transformed into the competent Escherichia coli DH5R T1R strain. Salmonella enterica subsp. enterica serovar Typhimurium

Protein Variants

EC Number Protein Variants Comment Organism
4.3.1.7 R160A Assembles into an oligomer, catalytically inactive, reacts with substrates to form magnetically isolated Co2+ and unidentified radical species, activity is resurrected by externally added guanidinium to 2.3% of wild-type. R160A EutB is unstable and forms strongly associated, high molecular mass aggregates. Salmonella enterica subsp. enterica serovar Typhimurium
4.3.1.7 R160E mutant fails to assemble into an oligomer Salmonella enterica subsp. enterica serovar Typhimurium
4.3.1.7 R160I mutant fails to assemble into an oligomer Salmonella enterica subsp. enterica serovar Typhimurium
4.3.1.7 R160K assembles into an oligomer, mutant displays catalytic turnover of aminoethanol, with a 180-fold lower value of kcat/KM relative to wild-type enzyme, forms Co2-substrate radical pair intermediate states during turnover on aminoethanol and (S)-2-aminopropanol substrates Salmonella enterica subsp. enterica serovar Typhimurium

KM Value [mM]

EC Number KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
4.3.1.7 0.0136
-
ethanolamine wild-type Salmonella enterica subsp. enterica serovar Typhimurium
4.3.1.7 0.41
-
ethanolamine R160K EAL shows a 30fold increase relative to wild-type enzyme Salmonella enterica subsp. enterica serovar Typhimurium

Localization

EC Number Localization Comment Organism GeneOntology No. Textmining

Molecular Weight [Da]

EC Number Molecular Weight [Da] Molecular Weight Maximum [Da] Comment Organism
4.3.1.7 32100
-
eutC protein subunit contains 286 amino acids Salmonella enterica subsp. enterica serovar Typhimurium
4.3.1.7 49400
-
eutB protein subunit contains 453 amino acids and the active site Salmonella enterica subsp. enterica serovar Typhimurium
4.3.1.7 500000
-
whole enzyme, indicates that the two subunits are present in a EutB6EutC6 stoichiometry Salmonella enterica subsp. enterica serovar Typhimurium

Natural Substrates/ Products (Substrates)

EC Number Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
4.3.1.7 ethanolamine Salmonella enterica subsp. enterica serovar Typhimurium
-
acetaldehyde + NH3
-
?

Organism

EC Number Organism UniProt Comment Textmining
4.3.1.7 Salmonella enterica subsp. enterica serovar Typhimurium
-
-
-

Purification (Commentary)

EC Number Purification (Comment) Organism
4.3.1.7
-
Salmonella enterica subsp. enterica serovar Typhimurium

Specific Activity [micromol/min/mg]

EC Number Specific Activity Minimum [µmol/min/mg] Specific Activity Maximum [µmol/min/mg] Comment Organism
4.3.1.7 additional information
-
Externally added guanidine hydrochloride leads to significant R160A EAL enzyme activity under Vmax conditions, the activity of R160A EAL increases with guanidine hydrochloride concentration and reaches a maximum at 10 mM, which represents 2.3% of the activity of the wild-type control. The resurrection of enzyme activity in R160A EAL by externally added guanidine hydrochloride provides strong support that a positively charged arginine side chain in the active site is catalytically essential. Salmonella enterica subsp. enterica serovar Typhimurium

Substrates and Products (Substrate)

EC Number Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
4.3.1.7 (S)-2-aminopropanol
-
Salmonella enterica subsp. enterica serovar Typhimurium ?
-
?
4.3.1.7 ethanolamine
-
Salmonella enterica subsp. enterica serovar Typhimurium acetaldehyde + NH3
-
?

Subunits

EC Number Subunits Comment Organism
4.3.1.7 oligomer Two subunits are present in a EutB6EutC6 stoichiometry, EAL is composed of a 453-residue EutB protein subunit and a 286-residue EutC protein subunit, which are coded by the eutb and eutc genes. The positive charge at the terminus of the R160 side chain of EutB is required to achieve the native EutB protein fold and the oligomeric structure of EAL Salmonella enterica subsp. enterica serovar Typhimurium

Synonyms

EC Number Synonyms Comment Organism
4.3.1.7 AEL
-
Salmonella enterica subsp. enterica serovar Typhimurium
4.3.1.7 ethanolamine ammonia-lyase
-
Salmonella enterica subsp. enterica serovar Typhimurium
4.3.1.7 ethanolamine deaminase
-
Salmonella enterica subsp. enterica serovar Typhimurium
4.3.1.7 EutB
-
Salmonella enterica subsp. enterica serovar Typhimurium

Turnover Number [1/s]

EC Number Turnover Number Minimum [1/s] Turnover Number Maximum [1/s] Substrate Comment Organism Structure
4.3.1.7 additional information
-
additional information mutant R160A displays no detectable catalytic turnover with ethanolamine as subtrate Salmonella enterica subsp. enterica serovar Typhimurium
4.3.1.7 8.5
-
ethanolamine R160K EAL Salmonella enterica subsp. enterica serovar Typhimurium
4.3.1.7 52.2
-
ethanolamine wild-type Salmonella enterica subsp. enterica serovar Typhimurium

pH Optimum

EC Number pH Optimum Minimum pH Optimum Maximum Comment Organism
4.3.1.7 7.5
-
assay at Salmonella enterica subsp. enterica serovar Typhimurium

Cofactor

EC Number Cofactor Comment Organism Structure
4.3.1.7 coenzyme B12 adenosylcobalamin Salmonella enterica subsp. enterica serovar Typhimurium