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The two reactions compared are done so using a Tanimoto similarity score (for more information, please see the MACiE FAQ) for the bond changes only. The score maay range from 0 to 1 where 1 indicates that the two reactions are identical at the bond change level and 0 indicates that there are no bond changes in common.


Key

1.0-0.9 0.9-0.8 0.8-0.7 0.7-0.6 0.6-0.5 0.5-0.4 0.4-0.3 0.3-0.2 0.2-0.1 0.1-0.0 =0

Results for Comparison of M0276 and M0144

These two reactions have a combined similarity of 0.17


M0276

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Comparison

M0144

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EC 1.7.99.4
nitrate reductase
Sub-Class EC 1.20.98.1
arsenite oxidase

Image of electron donor

Image of nitrate

Image of proton

right arrow

Image of water

Image of nitrite

Image of electron acceptor

electron donor
C00030
CHEBI:15022
nitrate
C00244
CHEBI:17632
2 proton
C00080
CHEBI:24636
water
C00001
CHEBI:15377
nitrite
C00088
CHEBI:16301
electron acceptor
C00028
CHEBI:17654
0

Image of oxidised azurin

Image of water

Image of arsenite

right arrow

Image of proton

Image of reduced azurin

Image of arsenate

oxidised azurin
C05357
water
C00001
CHEBI:15377
arsenite
C06697
CHEBI:29243
2 proton
C00080
CHEBI:24636
reduced azurin
C05358
arsenate
C11215
CHEBI:48597

Catalytic CATH Codes

3.40.228.10
0.0.0.0

Catalytic CATH Codes

3.40.228.10
2.102.10.10
0.0.0.0

Active Site



0.05264

Active Site



Catalytic Residues

Type Number Chain Location of Function
Lys 56 A Side Chain
Gly 383 A Main Chain Amide
Glu 384 A Side Chain
Met 153 A Side Chain
Met 346 A Side Chain
Cys 152 A Side Chain
0.0476

Catalytic Residues

Type Number Chain Location of Function
Cys 24 A Side Chain
Ser 98 A Main Chain Carbonyl
Ser 99 A Main Chain Amide
Ser 238 A Main Chain Carbonyl
His 62 B Side Chain
His 81 B Side Chain

Organic Cofactors

Type Identity Chain
Molybdopterin guanosine dinucleotide MGD 1803 A
Molybdopterin guanosine dinucleotide MGD 1804 A

Organic Cofactors

Type Identity Chain
Molybdopterin guanosine dinucleotide MGD 5002

Metal Cofactors

Type Het group Number Chain
iron SF4 1801 A
molybdenum MO 1802 A
iron HEC 1128 B
iron HEC 1129 B

Metal Cofactors

Type Het group Number Chain
molybdenum 4MO 5004 x
iron FS3 5005 x
iron FES 5006 x

Reaction occurs across 7 steps

0.25

Reaction occurs across 5 steps

Step 1
GIF of Reaction Step M0276.stg01

The nitrate oxyanion attacks the molybdenum coordination in a displacement reaction, eliminating the Cys152 sulfur which results in the formation of a disulfide bridge within the coordination sphere.
0 Step 1
GIF of Reaction Step M0144.stg01

Arsenic of the arsenite substrate attacks one of the molybdenum coordinating oxo groups, resulting in a Mo(VI) to Mo(IV) reduction.
Step 2
GIF of Reaction Step M0276.stg02

The nitrate ligand undergoes heterolytic dissociation from molybdenum to form the nitrite product. The oxygen ligand is left behind at the metal centre.
0 Step 2
GIF of Reaction Step M0144.stg02

The attacking oxo group forms a second bond to the arsenic, forming the product arsenate and resulting in the loss of the oxo group from the molybdenum complex and the remaining oxo group binding in a much stronger interaction.
Step 3
GIF of Reaction Step M0276.stg03

The close proximity iron sulfur cluster provides an electron to the molybdenum centre via a bridging lysine residue.
0 Step 3
GIF of Reaction Step M0144.stg03

An unidentified base activates water to attack the Mo(IV), forming a hydroxide group in place of the lost oxo group in a nucleophilic addition to the Mo(IV).
Step 4
GIF of Reaction Step M0276.stg04

A solvent molecule acts as a proton donor to the dianionic molybdenum centre.
0.5 Step 4
GIF of Reaction Step M0144.stg04

A second unidentified base deprotonates the Mo-bound hydroxide, reforming the oxo group. This results in a single electron transfer through the pterin portion of the cofactor, main chain carbonyl of Ser238, thiolate of Cys24, an iron-sulfur cluster, the peptide bond of Ser99-Ser98, His62B, a second iron-sulfur complex and His81B and finally yields the electron to a bound azurin and resulting in Mo(V).
Step 5
GIF of Reaction Step M0276.stg05

The close proximity iron sulfur cluster provides an electron to the molybdenum centre via a bridging lysine residue.
0 Step 5
GIF of Reaction Step M0144.stg05

The second single electron is transferred from Mo(V) through the pterin portion of the cofactor, main chain carbonyl of Ser238, thiolate of Cys24, an iron-sulfur cluster, the peptide bond of Ser99-Ser98, His62B, a second iron-sulfur complex and His81B and finally yields the electron to a bound azurin. This regenerates the enzyme's Mo(VI) oxidation state.
Step 6
GIF of Reaction Step M0276.stg06

A solvent molecule acts as a proton donor, forming a water ligand within the metal coordination sphere.
N/A Step 6
No Step with this number present
Step 7
GIF of Reaction Step M0276.stg07

The Cys152 sulfur atom substitutes the water molecule coordinated to the molybdenum centre.
N/A Step 7
No Step with this number present

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