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Literature summary for 5.1.1.1 extracted from

  • Shrestha, R.; Lockless, S.W.; Sorg, J.A.
    A Clostridium difficile alanine racemase affects spore germination and accommodates serine as a substrate (2017), J. Biol. Chem., 292, 10735-10742 .
    View publication on PubMedView publication on EuropePMC
Search for more literature for 5.1.1.1

Cloned(Commentary)

Cloned (Comment) Organism
gene alr2, recombinant expression of wild-type and mutant enzymes in Escherichia coli strain BL21(DE3) Clostridioides difficile

Protein Variants

Protein Variants Comment Organism
K39A site-directed mutagenesis, kinetically inactive mutant, the mutation disrupts the binding of the cofactor that is essential for catalysis (pyridoxal 5'-phosphate), the mutant shows altered binding kinetics with L-alanine and D-alanine, weak binding to L- and D-serine Clostridioides difficile
additional information construction of a alr2 knockout mutant RS07 generated by retargeting the pJS107 TargeTron plasmid. Complementation by expression of plasmid pRS89 encoding gene alr2. The alr2 mutant spores more readily germinate in response to L-alanine as a co-germinant, D-alanine also functions as a co-germinant, no germination in presence of taurocholic acid Clostridioides difficile

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
0.046
-
 L-alanine pH 7.5, 37°C, recombinant mutant K39A Clostridioides difficile
0.064
-
 L-alanine pH 7.5, 37°C, recombinant wild-type enzyme Clostridioides difficile

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
L-alanine Clostridioides difficile
-
 D-alanine
-
 r
L-alanine Clostridioides difficile 630
-
 D-alanine
-
 r
additional information Clostridioides difficile Alr2 can interconvert L- and D-serine and Alr2 binds to L- and D-serine with 2fold weaker affinity to that of L- and D-alanine, cf. EC 5.1.1.18 ?
-
 ?
additional information Clostridioides difficile 630 Alr2 can interconvert L- and D-serine and Alr2 binds to L- and D-serine with 2fold weaker affinity to that of L- and D-alanine, cf. EC 5.1.1.18 ?
-
 ?

Organism

Organism UniProt Comment Textmining
Clostridioides difficile Q180W0 i.e. Clostridium difficile strain UK1
-
Clostridioides difficile 630 Q180W0 i.e. Clostridium difficile strain UK1
-

Purification (Commentary)

Purification (Comment) Organism
recombinant wild-type and mutant enzymes from Escherichia coli strain BL21(DE3) by nickel affinity chromatography, dialysis, and gel filtration Clostridioides difficile

Source Tissue

Source Tissue Comment Organism Textmining

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
L-alanine
-
 Clostridioides difficile D-alanine
-
 r
L-alanine
-
 Clostridioides difficile 630 D-alanine
-
 r
additional information Alr2 can interconvert L- and D-serine and Alr2 binds to L- and D-serine with 2fold weaker affinity to that of L- and D-alanine, cf. EC 5.1.1.18 Clostridioides difficile ?
-
 ?
additional information Alr2 converts L-serine to an approximately equal amount of D-serine. When tested with D-serine, Alr2 does not convert as much, and nearly 75% of the D-serine remains in the D-form Clostridioides difficile ?
-
 ?
additional information Alr2 can interconvert L- and D-serine and Alr2 binds to L- and D-serine with 2fold weaker affinity to that of L- and D-alanine, cf. EC 5.1.1.18 Clostridioides difficile 630 ?
-
 ?
additional information Alr2 converts L-serine to an approximately equal amount of D-serine. When tested with D-serine, Alr2 does not convert as much, and nearly 75% of the D-serine remains in the D-form Clostridioides difficile 630 ?
-
 ?

Synonyms

Synonyms Comment Organism
ALR2
-
 Clostridioides difficile
Alr2 racemase
-
 Clostridioides difficile

Temperature Optimum [°C]

Temperature Optimum [°C] Temperature Optimum Maximum [°C] Comment Organism
37
-
 assay at Clostridioides difficile

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
7.5
-
 assay at Clostridioides difficile

Cofactor

Cofactor Comment Organism Structure
pyridoxal 5'-phosphate dependent on Clostridioides difficile

General Information

General Information Comment Organism
additional information Alr2 racemase is the sixth most highly expressed gene during Clostridium difficile spore formation Clostridioides difficile
physiological function many endospore-forming bacteria embed alanine racemases into their spore coats, and these enzymes are thought to convert the L-alanine germinant into D-alanine, a spore germination inhibitor. Clostridium difficile spores can respond to a diverse set of amino acid co-germinants and Alr2 can accommodate serine as a substrate. L-alanine is a co-germinant, and D-alanine also functions as a co-germinant. L- and D-serine are also co-germinants for Clostridium difficile spores. Only the L-form of alanine can trigger spore germination when added with taurocholic acid. Gene alr2 is dispensable for germination in response to L-alanine but essential for germination in response to D-alanine Clostridioides difficile