Literature summary for 4.3.1.1 extracted from

Fibriansah, G.; Veetil, V.P.; Poelarends, G.J.; Thunnissen, A.M.
Structural basis for the catalytic mechanism of aspartate ammonia lyase (2011), Biochemistry, 50, 6053-6062.

Crystallization (Commentary)

Crystallization (Comment)	Organism
in an unliganded state and in complex with L-aspartate at 2.4 and 2.6 A resolution, respectively. AspB forces the bound substrate to adopt a high-energy, enediolate-like conformation that is stabilized, in part, by an extensive network of hydrogen bonds between residues Thr101, Ser140, Thr141, and Ser319 and the substrate's beta-carboxylate group. Substrate binding induces a large conformational change in the SS loop, residuesG317SSIMPGKVN326, from an open conformation to one that closes over the active site. In the closed conformation, the strictly conserved SS loop residue Ser318 is at a suitable position to act as a catalytic base, abstracting the Cbeta proton of the substrate in the first step of the reaction mechanism. The small C-terminal domain of AspB plays an important role in controlling the conformation of the SS loop	Bacillus sp. (in: Bacteria)

Crystallization (Comment)

Organism

in an unliganded state and in complex with L-aspartate at 2.4 and 2.6 A resolution, respectively. AspB forces the bound substrate to adopt a high-energy, enediolate-like conformation that is stabilized, in part, by an extensive network of hydrogen bonds between residues Thr101, Ser140, Thr141, and Ser319 and the substrate's beta-carboxylate group. Substrate binding induces a large conformational change in the SS loop, residuesG317SSIMPGKVN326, from an open conformation to one that closes over the active site. In the closed conformation, the strictly conserved SS loop residue Ser318 is at a suitable position to act as a catalytic base, abstracting the Cbeta proton of the substrate in the first step of the reaction mechanism. The small C-terminal domain of AspB plays an important role in controlling the conformation of the SS loop

Bacillus sp. (in: Bacteria)

Protein Variants

Protein Variants	Comment	Organism
I320A	SS-loop mutant, about 2% of wild-type activity	Bacillus sp. (in: Bacteria)
M321A	SS-loop mutant, less than 1% of wild-type activity	Bacillus sp. (in: Bacteria)
P322A	SS-loop mutant, about 70% of wild-type activity	Bacillus sp. (in: Bacteria)
S318A	SS-loop mutant, complete loss of activity	Bacillus sp. (in: Bacteria)
S319A	SS-loop mutant, about 30% of wild-type activity	Bacillus sp. (in: Bacteria)

KM Value [mM]

KM Value [mM]	KM Value Maximum [mM]	Substrate	Comment	Organism
11	-	L-aspartate	mutant P322A, pH 8.5, 25°C	Bacillus sp. (in: Bacteria)
15	-	L-aspartate	wild-type, pH 8.5, 25°C	Bacillus sp. (in: Bacteria)
28	-	L-aspartate	mutant S319A, pH 8.5, 25°C	Bacillus sp. (in: Bacteria)

Organism

Organism	UniProt	Comment	Textmining
Bacillus sp. (in: Bacteria)	Q9LCC6	-	-
Bacillus sp. (in: Bacteria) YM55-1	Q9LCC6	-	-

Substrates and Products (Substrate)

Substrates	Comment Substrates	Organism	Products	Comment (Products)	Rev.	Reac.
L-aspartate	-	Bacillus sp. (in: Bacteria)	fumarate + NH3	-	?
L-aspartate	-	Bacillus sp. (in: Bacteria) YM55-1	fumarate + NH3	-	?

Synonyms

Synonyms	Comment	Organism
aspB	-	Bacillus sp. (in: Bacteria)

Turnover Number [1/s]

Turnover Number Minimum [1/s]	Turnover Number Maximum [1/s]	Substrate	Comment	Organism
17	-	L-aspartate	mutant S319A, pH 8.5, 25°C	Bacillus sp. (in: Bacteria)
21	-	L-aspartate	mutant P322A, pH 8.5, 25°C	Bacillus sp. (in: Bacteria)
40	-	L-aspartate	wild-type, pH 8.5, 25°C	Bacillus sp. (in: Bacteria)

kcat/KM [mM/s]

kcat/KM Value [1/mMs^-1]	kcat/KM Value Maximum [1/mMs^-1]	Substrate	Comment	Organism
0.008	-	L-aspartate	mutant M321A, pH 8.5, 25°C	Bacillus sp. (in: Bacteria)
0.055	-	L-aspartate	mutant I320A, pH 8.5, 25°C	Bacillus sp. (in: Bacteria)
0.61	-	L-aspartate	mutant S319A, pH 8.5, 25°C	Bacillus sp. (in: Bacteria)
1.9	-	L-aspartate	mutant P322A, pH 8.5, 25°C	Bacillus sp. (in: Bacteria)
2.7	-	L-aspartate	wild-type, pH 8.5, 25°C	Bacillus sp. (in: Bacteria)