title: Calcium-independent calmodulin binding and two-metal-ion catalytic mechanism of anthrax edema factor.
abstract: Edema factor (EF), a key anthrax exotoxin, has an anthrax protective antigen-binding domain (PABD) and a calmodulin (CaM)-activated adenylyl cyclase domain. Here, we report the crystal structures of CaM-bound EF, revealing the architecture of EF PABD. CaM has N- and C-terminal domains and each domain can bind two calcium ions. Calcium binding induces the conformational change of CaM from closed to open. Structures of the EF-CaM complex show how EF locks the N-terminal domain of CaM into a closed conformation regardless of its calcium-loading state. This represents a mechanism of how CaM effector alters the calcium affinity of CaM and uncouples the conformational change of CaM from calcium loading. Furthermore, structures of EF-CaM complexed with nucleotides show that EF uses two-metal-ion catalysis, a prevalent mechanism in DNA and RNA polymerases. A histidine (H351) further facilitates the catalysis of EF by activating a water to deprotonate 3'OH of ATP. Mammalian adenylyl cyclases share no structural similarity with EF and they also use two-metal-ion catalysis, suggesting the catalytic mechanism-driven convergent evolution of two structurally diverse adenylyl cyclases.
authors.affiliation: Ben-May Institute for Cancer Research, The University of Chicago, Chicago, IL 60637, USA.
authors.forename: Yuequan
authors.initials: Y
authors.lastname: Shen
authors.forename: Natalia L
authors.initials: NL
authors.lastname: Zhukovskaya
authors.forename: Qing
authors.initials: Q
authors.lastname: Guo
authors.forename: Jan
authors.initials: J
authors.lastname: Florián
authors.forename: Wei-Jen
authors.initials: WJ
authors.lastname: Tang
mesh_terms: D037361:Adenylate Cyclase Toxin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000262:Adenylyl Cyclases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D000942:Antigens, Bacterial; D001408:Bacillus anthracis / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D001427:Bacterial Toxins; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism; D002147:Calmodulin / Q000737:chemistry / Q000378:metabolism*; D002384:Catalysis; D018360:Crystallography, X-Ray; D005098:Exotoxins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D005964:Glucosyltransferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D006639:Histidine / Q000737:chemistry; D008670:Metals / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
chemical_list: D037361:Adenylate Cyclase Toxin; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D002147:Calmodulin; D005098:Exotoxins; D008670:Metals; D046912:Multiprotein Complexes; D011994:Recombinant Proteins; C030325:anthrax toxin; D006639:Histidine; C111504:ExoY protein, bacteria; D005964:Glucosyltransferases; D000262:Adenylyl Cyclases; D002118:Calcium
references.citation: Trends Microbiol. 1999 Apr;7(4):172-6
references.pmid: 10217833
references.citation: Physiol Rev. 1999 Jul;79(3):661-82
references.pmid: 10390515
references.citation: Science. 1999 Jul 30;285(5428):756-60
references.pmid: 10427002
references.citation: J Mol Graph Model. 1998 Aug-Dec;16(4-6):213-25, 261
references.pmid: 10522241
references.citation: Chem Biol. 1999 Dec;6(12):901-8
references.pmid: 10631518
references.citation: Infect Immun. 2000 Apr;68(4):1781-6
references.pmid: 10722564
references.citation: Biochemistry. 2000 Jun 6;39(22):6706-13
references.pmid: 10828989
references.citation: EMBO J. 2001 Feb 1;20(3):433-45
references.pmid: 11157750
references.citation: Nat Struct Biol. 2001 Apr;8(4):290-3
references.pmid: 11276242
references.citation: Nature. 2001 Apr 26;410(6832):1120-4
references.pmid: 11323678
references.citation: Acta Crystallogr D Biol Crystallogr. 2001 Oct;57(Pt 10):1367-72
references.pmid: 11567147
references.citation: Nature. 2001 Nov 8;414(6860):229-33
references.pmid: 11700563
references.citation: J Biol Chem. 2002 Jan 25;277(4):3006-10
references.pmid: 11714723
references.citation: Acta Crystallogr D Biol Crystallogr. 2001 Dec;57(Pt 12):1881-4
references.pmid: 11717504
references.citation: Nature. 2002 Jan 24;415(6870):396-402
references.pmid: 11807546
references.citation: Cell. 2002 Mar 22;108(6):739-42
references.pmid: 11955428
references.citation: Proc Natl Acad Sci U S A. 2002 May 14;99(10):7049-53
references.pmid: 11997439
references.citation: Curr Opin Struct Biol. 2002 Jun;12(3):289-95
references.pmid: 12127446
references.citation: Proc Natl Acad Sci U S A. 2002 Sep 17;99(19):12067-72
references.pmid: 12221284
references.citation: EMBO J. 2002 Dec 16;21(24):6721-32
references.pmid: 12485993
references.citation: J Biol Chem. 2003 May 23;278(21):19111-7
references.pmid: 12637534
references.citation: J Biol Chem. 2003 Jul 11;278(28):25990-7
references.pmid: 12676933
references.citation: J Biol Chem. 2003 Aug 1;278(31):29261-6
references.pmid: 12724328
references.citation: J Am Chem Soc. 2003 Jul 9;125(27):8163-77
references.pmid: 12837086
references.citation: J Biol Chem. 2003 Oct 3;278(40):38514-21
references.pmid: 12885782
references.citation: Structure. 2003 Oct;11(10):1303-7
references.pmid: 14527397
references.citation: Annu Rev Cell Dev Biol. 2003;19:45-70
references.pmid: 14570563
references.citation: Cell Signal. 2003 Dec;15(12):1081-9
references.pmid: 14575863
references.citation: Structure. 2004 May;12(5):849-60
references.pmid: 15130477
references.citation: J Biol Chem. 2004 Jul 9;279(28):29427-35
references.pmid: 15131111
references.citation: Mol Microbiol. 2004 Jun;52(5):1229-42
references.pmid: 15165228
references.citation: Biochim Biophys Acta. 2004 Dec 6;1742(1-3):69-79
references.pmid: 15590057
references.citation: J Exp Med. 2005 Feb 7;201(3):325-31
references.pmid: 15699068
references.citation: J Biol Chem. 1992 May 15;267(14):9816-20
references.pmid: 1577816
references.citation: J Biol Chem. 1991 May 5;266(13):8595-603
references.pmid: 2022671
references.citation: Acta Crystallogr A. 1991 Mar 1;47 ( Pt 2):110-9
references.pmid: 2025413
references.citation: Biochemistry. 1990 May 22;29(20):4922-8
references.pmid: 2114169
references.citation: Methods Enzymol. 1997;276:307-26
references.pmid: 27754618
references.citation: Protein Eng. 1994 Mar;7(3):385-91
references.pmid: 8177887
references.citation: J Mol Graph. 1996 Feb;14(1):33-8, 27-8
references.pmid: 8744570
references.citation: Biochemistry. 1996 Oct 1;35(39):12742-61
references.pmid: 8841118
references.citation: Structure. 1997 Jan 15;5(1):95-108
references.pmid: 9016716
references.citation: Nature. 1998 Jan 15;391(6664):231-2
references.pmid: 9440683
references.citation: Curr Opin Struct Biol. 1998 Feb;8(1):54-63
references.pmid: 9519297
references.citation: Science. 1998 Jun 26;280(5372):2129-32
references.pmid: 9641921
references.citation: Annu Rev Biophys Biomol Struct. 1998;27:133-64
references.pmid: 9646865
references.citation: Acta Crystallogr D Biol Crystallogr. 1998 Sep 1;54(Pt 5):905-21
references.pmid: 9757107
references.citation: Proc Natl Acad Sci U S A. 1998 Nov 10;95(23):13899-904
references.pmid: 9811898