DB code: D00867

RLCP classification 3.1197.15020.136 : Transfer
5.115.129300.66 : Elimination
3.1177.220080.38 : Transfer
CATH domain 3.40.47.10 : Peroxisomal Thiolase; Chain A, domain 1 Catalytic domain
3.40.47.10 : Peroxisomal Thiolase; Chain A, domain 1 Catalytic domain
E.C. 2.3.1.180
CSA
M-CSA
MACiE

CATH domain Related DB codes (homologues)
3.40.47.10 : Peroxisomal Thiolase; Chain A, domain 1 D00090 D00411 D00509 D00825 D00826 D00871

Uniprot Enzyme Name
UniprotKB Protein name Synonyms RefSeq Pfam
O67185 3-oxoacyl-[acyl-carrier-protein] synthase 3
EC 2.3.1.180
3-oxoacyl-[acyl-carrier-protein] synthase III
Beta-ketoacyl-ACP synthase III
KAS III
NP_213748.1 (Protein)
NC_000918.1 (DNA/RNA sequence)
PF08545 (ACP_syn_III)
PF08541 (ACP_syn_III_C)
[Graphical View]
Q820T1 3-oxoacyl-[acyl-carrier-protein] synthase 3
EC 2.3.1.180
3-oxoacyl-[acyl-carrier-protein] synthase III
Beta-ketoacyl-ACP synthase III
KAS III
NP_816505.1 (Protein)
NC_004668.1 (DNA/RNA sequence)
PF08545 (ACP_syn_III)
PF08541 (ACP_syn_III_C)
[Graphical View]

KEGG enzyme name
Beta-ketoacyl-acyl-carrier-protein synthase III
3-Oxoacyl:ACP synthase III
3-Ketoacyl-acyl carrier protein synthase III
KASIII
KAS III
FabH
Beta-ketoacyl-acyl carrier protein synthase III
Beta-ketoacyl-ACP synthase III
Beta-ketoacyl (acyl carrier protein) synthase III
Beta-ketoacyl-[acyl-carrier-protein] synthase III
Acetyl-CoA:malonyl-[acyl-carrier-protein] C-acyltransferase

UniprotKB: Accession Number Entry name Activity Subunit Subcellular location Cofactor
Q820T1 FABH_ENTFA Acetyl-CoA + malonyl-[acyl-carrier-protein] = acetoacyl-[acyl-carrier-protein] + CoA + CO2. Homodimer (By similarity). Cytoplasm (Probable).
O67185 FABH_AQUAE Acetyl-CoA + malonyl-[acyl-carrier-protein] = acetoacyl-[acyl-carrier-protein] + CoA + CO2. Homodimer (By similarity). Cytoplasm (Probable).

KEGG Pathways
Map code Pathways E.C.
MAP00061 Fatty acid biosynthesis

Compound table
Substrates Products Intermediates
KEGG-id C00024 C01209 C05744 C00010 C00011 I00132 I00133 I00134 I00135
E.C.
Compound acetyl-CoA malonyl-[acyl-carrier protein] acetoacetyl-[acyl-carrier protein] CoA CO2 Peptidyl-Cys-tetrahedral-acetyl-CoA Peptidyl-Cys-S-acetyl [Acyl-carrier protein]-decarboxylated malonyl group (Peptidyl-Ser-phosphopantetheine-S-enolate) Peptidyl-Cys-tetrahedral-acetyl-keto-[acyl-carrier protein]
Type amine group,carbohydrate,nucleotide ,peptide/protein,sulfide group carbohydrate,carboxyl group,peptide/protein,phosphate group/phosphate ion,sulfide group carbohydrate,peptide/protein,phosphate group/phosphate ion,sulfide group amine group,carbohydrate,nucleotide ,peptide/protein,sulfhydryl group others
ChEBI 15351
15346
16526
PubChem 444493
6302
6816
87642
280
2ebdA01 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
2ebdB01 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
3il4A01 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Bound:ACO Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
3il4B01 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Bound:ACO Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
3il4C01 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Bound:ACO Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
3il4D01 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Bound:ACO Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
3il5A01 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
3il5B01 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
3il5C01 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
3il5D01 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
3il6A01 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound Unbound Unbound Unbound Intermediate-bound:SCY Unbound Unbound
2ebdA02 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
2ebdB02 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
3il4A02 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
3il4B02 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
3il4C02 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
3il4D02 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
3il5A02 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
3il5B02 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
3il5C02 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
3il5D02 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
3il6A02 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound

Reference for Active-site residues
resource references E.C.
literature [2], [3], [5], [9], [10], [13], [14], [15], [18], [21] & Swiss-prot;O67185, P0A6R0, P43711, Q6GIA4, Q820T1, Q8NXE2

Active-site residues
PDB Catalytic residues Cofactor-binding residues Modified residues Main-chain involved in catalysis Comment
2ebdA01 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain CYS 111;GLU 139 CYS 111
2ebdB01 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain CYS 111;GLU 139 CYS 111
3il4A01 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain CYS 117;GLU 145 CYS 117
3il4B01 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain CYS 117;GLU 145 CYS 117
3il4C01 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain CYS 117;GLU 145 CYS 117
3il4D01 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain CYS 117;GLU 145 CYS 117
3il5A01 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain CYS 117;GLU 145 CYS 117
3il5B01 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain CYS 117;GLU 145 CYS 117
3il5C01 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain CYS 117;GLU 145 CYS 117
3il5D01 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain CYS 117;GLU 145 CYS 117
3il6A01 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain ;GLU 145 SCY 117(S-acetyl-cysteine) SCY 117
2ebdA02 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain HIS 236;ASN 266;SER 268 GLY 298
2ebdB02 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain HIS 236;ASN 266;SER 268 GLY 298
3il4A02 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain HIS 250;ASN 280;SER 282 GLY 314 mutant A192T, N253S, invisible 211-212
3il4B02 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain HIS 250;ASN 280;SER 282 GLY 314 mutant A192T, N253S, invisible 211-212
3il4C02 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain HIS 250;ASN 280;SER 282 GLY 314 mutant A192T, N253S, invisible 211-212
3il4D02 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain HIS 250;ASN 280;SER 282 GLY 314 mutant A192T, N253S, invisible 211-212
3il5A02 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain HIS 250;ASN 280;SER 282 GLY 314
3il5B02 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain HIS 250;ASN 280;SER 282 GLY 314
3il5C02 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain HIS 250;ASN 280;SER 282 GLY 314
3il5D02 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain HIS 250;ASN 280;SER 282 GLY 314
3il6A02 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain HIS 250;ASN 280;SER 282 GLY 314

References for Catalytic Mechanism
References Sections No. of steps in catalysis
[2]
Fig.6A, p.36467-36470
[3]
Scheme 1, p.158-160
[5]
Fig.7b, 3p.190-192
[9]
p.349-352
[10]
p.1561-1565
[13]
Fig.6b, p.806-809
[14]
Fig.6, p.32544-32547
[15]
Fig.1
[18]
Fig.1B
[21]
Fig.5, p.696-697

References
[1]
Resource
Comments X-RAY CRYSTALLOGRAPHY (2.3 ANGSTROMS).
Medline ID
PubMed ID 10571059
Journal FEBS Lett
Year 1999
Volume 460
Pages 46-52
Authors Olsen JG, Kadziola A, von Wettstein-Knowles P, Siggaard-Andersen M, Lindquist Y, Larsen S
Title The X-ray crystal structure of beta-ketoacyl [acyl carrier protein] synthase I.
Related PDB 1dd8
Related UniProtKB P0A953
[2]
Resource
Comments X-RAY CRYSTALLOGRAPHY (2.0 ANGSTROMS).
Medline ID
PubMed ID 10593943
Journal J Biol Chem
Year 1999
Volume 274
Pages 36465-71
Authors Qiu X, Janson CA, Konstantinidis AK, Nwagwu S, Silverman C, Smith WW, Khandekar S, Lonsdale J, Abdel-Meguid SS
Title Crystal structure of beta-ketoacyl-acyl carrier protein synthase III. A key condensing enzyme in bacterial fatty acid biosynthesis.
Related PDB 1d9b 1hn9
Related UniProtKB P0A6R0
[3]
Resource
Comments
Medline ID
PubMed ID 10600651
Journal Biochem J
Year 2000
Volume 345 Pt 1
Pages 153-60
Authors Abbadi A, Brummel M, Schutt BS, Slabaugh MB, Schuch R, Spener F
Title Reaction mechanism of recombinant 3-oxoacyl-(acyl-carrier-protein) synthase III from Cuphea wrightii embryo, a fatty acid synthase type II condensing enzyme.
Related PDB
Related UniProtKB
[4]
Resource
Comments
Medline ID
PubMed ID 11006298
Journal J Biol Chem
Year 2000
Volume 275
Pages 39640-6
Authors Jez JM, Noel JP
Title Mechanism of chalcone synthase. pKa of the catalytic cysteine and the role of the conserved histidine in a plant polyketide synthase.
Related PDB
Related UniProtKB
[5]
Resource
Comments X-RAY CRYSTALLOGRAPHY (1.8 ANGSTROMS).
Medline ID
PubMed ID 10673437
Journal Structure
Year 2000
Volume 8
Pages 185-95
Authors Davies C, Heath RJ, White SW, Rock CO
Title The 1.8 A crystal structure and active-site architecture of beta-ketoacyl-acyl carrier protein synthase III (FabH) from escherichia coli.
Related PDB 1ebl
Related UniProtKB P0A6R0
[6]
Resource
Comments
Medline ID
PubMed ID 11502177
Journal Biochemistry
Year 2001
Volume 40
Pages 9836-45
Authors McGuire KA, Siggaard-Andersen M, Bangera MG, Olsen JG, von Wettstein-Knowles P
Title beta-Ketoacyl-[acyl carrier protein] synthase I of Escherichia coli: aspects of the condensation mechanism revealed by analyses of mutations in the active site pocket.
Related PDB
Related UniProtKB
[7]
Resource
Comments X-RAY CRYSTALLOGRAPHY (2.1 ANGSTROMS).
Medline ID
PubMed ID 11278743
Journal J Biol Chem
Year 2001
Volume 276
Pages 20516-22
Authors Scarsdale JN, Kazanina G, He X, Reynolds KA, Wright HT
Title Crystal structure of the Mycobacterium tuberculosis beta-ketoacyl-acyl carrier protein synthase III.
Related PDB 1hzp
Related UniProtKB P0A574
[8]
Resource
Comments
Medline ID
PubMed ID 11078736
Journal J Biol Chem
Year 2001
Volume 276
Pages 8231-8
Authors Zhang YM, Rao MS, Heath RJ, Price AC, Olson AJ, Rock CO, White SW
Title Identification and analysis of the acyl carrier protein (ACP) docking site on beta-ketoacyl-ACP synthase III.
Related PDB
Related UniProtKB
[9]
Resource
Comments X-RAY CRYSTALLOGRAPHY (1.9 ANGSTROMS).
Medline ID
PubMed ID 11243824
Journal J Mol Biol
Year 2001
Volume 307
Pages 341-56
Authors Qiu X, Janson CA, Smith WW, Head M, Lonsdale J, Konstantinidis AK
Title Refined structures of beta-ketoacyl-acyl carrier protein synthase III.
Related PDB 1hnd 1hnh 1hnj 1hnk
Related UniProtKB P0A6R0
[10]
Resource
Comments X-RAY CRYSTALLOGRAPHY (2.1 ANGSTROMS).
Medline ID
PubMed ID 12429097
Journal Structure
Year 2002
Volume 10
Pages 1559-68
Authors Pan H, Tsai S, Meadows ES, Miercke LJ, Keatinge-Clay AT, O'Connell J, Khosla C, Stroud RM
Title Crystal structure of the priming beta-ketosynthase from the R1128 polyketide biosynthetic pathway.
Related PDB 1mzj
Related UniProtKB Q9F6D4
[11]
Resource
Comments
Medline ID
PubMed ID 12502353
Journal J Med Chem
Year 2003
Volume 46
Pages 5-8
Authors Daines RA, Pendrak I, Sham K, Van Aller GS, Konstantinidis AK, Lonsdale JT, Janson CA, Qiu X, Brandt M, Khandekar SS, Silverman C, Head MS
Title First X-ray cocrystal structure of a bacterial FabH condensing enzyme and a small molecule inhibitor achieved using rational design and homology modeling.
Related PDB 1mzs
Related UniProtKB
[12]
Resource
Comments
Medline ID
PubMed ID 12866053
Journal Proteins
Year 2003
Volume 52
Pages 427-35
Authors Dawe JH, Porter CT, Thornton JM, Tabor AB
Title A template search reveals mechanistic similarities and differences in beta-ketoacyl synthases (KAS) and related enzymes.
Related PDB
Related UniProtKB
[13]
Resource
Comments
Medline ID
PubMed ID 15952903
Journal Annu Rev Biochem
Year 2005
Volume 74
Pages 791-831
Authors White SW, Zheng J, Zhang YM, Rock
Title The structural biology of type II fatty acid biosynthesis.
Related PDB
Related UniProtKB
[14]
Resource
Comments
Medline ID
PubMed ID 16040614
Journal J Biol Chem
Year 2005
Volume 280
Pages 32539-47
Authors Brown AK, Sridharan S, Kremer L, Lindenberg S, Dover LG, Sacchettini JC, Besra GS
Title Probing the mechanism of the Mycobacterium tuberculosis beta-ketoacyl-acyl carrier protein synthase III mtFabH: factors influencing catalysis and substrate specificity.
Related PDB 1m1m 2ahb 2aj9
Related UniProtKB
[15]
Resource
Comments
Medline ID
PubMed ID 15713483
Journal J Mol Biol
Year 2005
Volume 346
Pages 1313-21
Authors Musayev F, Sachdeva S, Scarsdale JN, Reynolds KA, Wright HT
Title Crystal structure of a substrate complex of Mycobacterium tuberculosis beta-ketoacyl-acyl carrier protein synthase III (FabH) with lauroyl-coenzyme A.
Related PDB 1u6e 1u6s
Related UniProtKB
[16]
Resource
Comments
Medline ID
PubMed ID 15987898
Journal Protein Sci
Year 2005
Volume 14
Pages 2087-94
Authors Qiu X, Choudhry AE, Janson CA, Grooms M, Daines RA, Lonsdale JT, Khandekar SS
Title Crystal structure and substrate specificity of the beta-ketoacyl-acyl carrier protein synthase III (FabH) from Staphylococcus aureus.
Related PDB 1zow
Related UniProtKB
[17]
Resource
Comments
Medline ID
PubMed ID 16356722
Journal Trends Biochem Sci
Year 2005
Volume 31
Pages 64-71
Authors Haapalainen AM, Merilainen G, Wierenga RK
Title The thiolase superfamily: condensing enzymes with diverse reaction specificities.
Related PDB
Related UniProtKB
[18]
Resource
Comments
Medline ID
PubMed ID 17524982
Journal Chem Biol
Year 2007
Volume 14
Pages 513-24
Authors Alhamadsheh MM, Musayev F, Komissarov AA, Sachdeva S, Wright HT, Scarsdale N, Florova G, Reynolds KA
Title Alkyl-CoA disulfides as inhibitors and mechanistic probes for FabH enzymes.
Related PDB 2eft 2gyo
Related UniProtKB
[19]
Resource
Comments
Medline ID
PubMed ID 18096200
Journal Bioorg Chem
Year 2008
Volume 36
Pages 85-90
Authors Sachdeva S, Musayev F, Alhamadsheh MM, Neel Scarsdale J, Tonie Wright H, Reynolds KA
Title Probing reactivity and substrate specificity of both subunits of the dimeric Mycobacterium tuberculosis FabH using alkyl-CoA disulfide inhibitors and acyl-CoA substrates.
Related PDB
Related UniProtKB
[20]
Resource
Comments
Medline ID
PubMed ID 18420147
Journal Chem Biol
Year 2008
Volume 15
Pages 402-12
Authors Sachdeva S, Musayev FN, Alhamadsheh MM, Scarsdale JN, Wright HT, Reynolds KA
Title Separate entrance and exit portals for ligand traffic in Mycobacterium tuberculosis FabH.
Related PDB 2qnz 2qny 2qnx 2qo0 2qo1
Related UniProtKB
[21]
Resource
Comments
Medline ID
PubMed ID 18824113
Journal Mol Phylogenet Evol
Year 2008
Volume 49
Pages 691-701
Authors Jiang C, Kim SY, Suh DY
Title Divergent evolution of the thiolase superfamily and chalcone synthase family.
Related PDB
Related UniProtKB
[22]
Resource
Comments
Medline ID
PubMed ID 19665020
Journal FEBS Lett
Year 2009
Volume 583
Pages 2939-46
Authors Gajiwala KS, Margosiak S, Lu J, Cortez J, Su Y, Nie Z, Appelt K
Title Crystal structures of bacterial FabH suggest a molecular basis for the substrate specificity of the enzyme.
Related PDB 3il3 3il4 3il5 3il6 3il7 3il9
Related UniProtKB

Comments
This enzyme belongs to chalcone synthase family in thiolase superfamily (see [21]). This enzyme is homologous to the counterpart enzymes from different bacteria (D00825 and D00826 in EzCatDB), with a slightly different catalytic site. Moreover, these enzymes are categorized in type III of beta-ketoacyl-acyl-carrier protein synthases (KAS).
According to the literature, the catalysis proceeds through the Ping-Pong reaction mechanism.
According to the literature [2], [3], [5], [9], [10], [14], [15] and [21], this enzyme catalyzes the following reactions:
(A) Transfer of acyl group from sulfur atom of acetyl-CoA to catalytic cysteine (see [9]):
(A0) Asn266 (of 2ebd) modulate the pKa of His236, whereas His236 may lower the pKa of the sidechain of Cys111.
(A1) Glu139 acts as a general base to deprotonate the nucleophile, Cys111, through the sidechain of Ser268. (Helix dipole moment may also activate the cysteine sidechain.)
(A2) The activated thiol group of Cys111 makes a nucleophilic attack on the acetyl group of acetyl-CoA, leading to a transition-state (I00132). The oxyanion hole, composed of the mainchain amide groups of Cys111 and Gly298, stabilizes the negative charge of the oxyanion on the tetrahedral transition-state (I00132).
(A3) His236 acts as a general acid to protonate the leaving sulfur atom of CoA, generating an acetyl group on Cys111 (I00133).
(B) Decarboxylation of malonyl-ACP (Elimination of carboxylate group from malonyl group) forming carbanion/enolate transition-state (I00134):
(B0) Asn266 and His236 interact with the carbonyl oxygen of the second substrate, malonyl-ACP, and stabilize it.
(B1) His236 may act as a general base to deprotonate the carboxylic group of malonyl-ACP, to facilitate the decarboxylation. This reaction generates a carbanion/enolate transition-state (I00134). The enolate is stabilized by Asn266 and His236.
(C) Transfer of acetyl group from catalytic cysteine to carbanion on the transition-state (I00134):
(C0) Asn266 and His236 stabilize the enol group of the transition-state (I00134).
(C1) The carbanion makes a nucleophilic attack on the acetyl group of the acetyl intermediate (I00133), forming a tetrahedral transition-state (I00135). The oxyanion of the tetrahedral transition-state (I00135) is stabilized by the oxyanion hole composed of the mainchain amide groups of Cys111 and Gly298.
(C2) Glu139 may act as a general acid to protonate the leaving catalytic residue, Cys111, through the sidechain of Ser268.

Created Updated
2009-11-26 2012-07-06