PDBsum entry 3e8a

Lyase/lyase inhibitor

PDB id: 3e8a

Contents

Protein chains

190 a.a. *

188 a.a. *

328 a.a. *

Ligands

FKP

AGS

GSP

Metals

_CA

_CL

_MG

Waters ×12

* Residue conservation analysis

Obsolete entry

PDB id:

3e8a

Name:

Lyase/lyase inhibitor

Title:

Complex of gs-alpha with the catalytic domains of mammalian adenylyl cyclase: complex with adenosine 5-o-(l- thiophosphate) and low ca concentration

Structure:

Adenylate cyclase type 5. Chain: a. Fragment: c1a domain. Synonym: adenylate cyclase type v, atp pyrophosphate-lyase 5, adenylyl cyclase 5, ca(2+)-inhibitable adenylyl cyclase. Engineered: yes. Mutation: yes. Adenylate cyclase type 2. Chain: b.

Source:

Canis lupus familiaris. Dogs. Organism_taxid: 9615. Gene: adcy5, adenylyl cyclase type v. Expressed in: escherichia coli. Expression_system_taxid: 562. Rattus norvegicus. Brown rat,rat,rats. Organism_taxid: 10116.

Resolution:

3.00Å R-factor: 0.242 R-free: 0.309

Authors:

T.-C.Mou,S.R.Sprang

Key ref:

T.C.Mou et al. (2009). Structural basis for inhibition of mammalian adenylyl cyclase by calcium. Biochemistry, 48, 3387-3397. PubMed id: 19243146

Date:

19-Aug-08 Release date: 12-May-09

Protein chain

P30803  (ADCY5_CANLF) -  Adenylate cyclase type 5 from Canis lupus familiaris

Seq: 1265 a.a.

Struc: 190 a.a.*

Protein chain

P26769  (ADCY2_RAT) -  Adenylate cyclase type 2 from Rattus norvegicus

Seq: 1090 a.a.

Struc: 188 a.a.

Protein chain

P04896  (GNAS2_BOVIN) -  Guanine nucleotide-binding protein G(s) subunit alpha isoforms short from Bos taurus

Seq: 394 a.a.

Struc: 328 a.a.

* PDB and UniProt seqs differ at 1 residue position (black cross)

Enzyme reactions

• Enzyme class: Chains A, B: E.C.4.6.1.1 - adenylate cyclase.
• Reaction: ATP = 3',5'-cyclic AMP + diphosphate

ATP (Bound ligand (Het Group name = AGS) matches with 93.75% similarity) = 3',5'-cyclic AMP + diphosphate

• Cofactor: Pyridoxal 5'-phosphate

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

reference

Biochemistry 48:3387-3397 (2009)

PubMed id: 19243146

Structural basis for inhibition of mammalian adenylyl cyclase by calcium.

T.C.Mou, N.Masada, D.M.Cooper, S.R.Sprang.

ABSTRACT

Type V and VI mammalian adenylyl cyclases (AC5, AC6) are inhibited by Ca(2+) at both sub- and supramicromolar concentration. This inhibition may provide feedback in situations where cAMP promotes opening of Ca(2+) channels, allowing fine control of cardiac contraction and rhythmicity in cardiac tissue where AC5 and AC6 predominate. Ca(2+) inhibits the soluble AC core composed of the C1 domain of AC5 (VC1) and the C2 domain of AC2 (IIC2). As observed for holo-AC5, inhibition is biphasic, showing "high-affinity" (K(i) = approximately 0.4 microM) and "low-affinity" (K(i) = approximately 100 microM) modes of inhibition. At micromolar concentration, Ca(2+) inhibition is nonexclusive with respect to pyrophosphate (PP(i)), a noncompetitive inhibitor with respect to ATP, but at >100 microM Ca(2+), inhibition appears to be exclusive with respect to PP(i). The 3.0 A resolution structure of Galphas.GTPgammaS/forskolin-activated VC1:IIC2 crystals soaked in the presence of ATPalphaS and 8 microM free Ca(2+) contains a single, loosely coordinated metal ion. ATP soaked into VC1:IIC2 crystals in the presence of 1.5 mM Ca(2+) is not cyclized, and two calcium ions are observed in the 2.9 A resolution structure of the complex. In both of the latter complexes VC1:IIC2 adopts the "open", catalytically inactive conformation characteristic of the apoenzyme, in contrast to the "closed", active conformation seen in the presence of ATP analogues and Mg(2+) or Mn(2+). Structures of the pyrophosphate (PP(i)) complex with 10 mM Mg(2+) (2.8 A) or 2 mM Ca(2+) (2.7 A) also adopt the open conformation, indicating that the closed to open transition occurs after cAMP release. In the latter complexes, Ca(2+) and Mg(2+) bind only to the high-affinity "B" metal site associated with substrate/product stabilization. Ca(2+) thus stabilizes the inactive conformation in both ATP- and PP(i)-bound states.