1ZOS

Structure of 5'-methylthionadenosine/S-Adenosylhomocysteine nucleosidase from S. pneumoniae with a transition-state inhibitor MT-ImmA


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.6 Å
  • R-Value Free: 0.211 
  • R-Value Work: 0.193 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Structure and inhibition of a quorum sensing target from Streptococcus pneumoniae.

Singh, V.Shi, W.Almo, S.C.Evans, G.B.Furneaux, R.H.Tyler, P.C.Painter, G.F.Lenz, D.H.Mee, S.Zheng, R.Schramm, V.L.

(2006) Biochemistry 45: 12929-12941

  • DOI: 10.1021/bi061184i

  • PubMed Abstract: 
  • Streptococcus pneumoniae 5'-methylthioadenosine/S-adenosylhomocysteine hydrolase (MTAN) catalyzes the hydrolytic deadenylation of its substrates to form adenine and 5-methylthioribose or S-ribosylhomocysteine (SRH). MTAN is not found in mammals but i ...

    Streptococcus pneumoniae 5'-methylthioadenosine/S-adenosylhomocysteine hydrolase (MTAN) catalyzes the hydrolytic deadenylation of its substrates to form adenine and 5-methylthioribose or S-ribosylhomocysteine (SRH). MTAN is not found in mammals but is involved in bacterial quorum sensing. MTAN gene disruption affects the growth and pathogenicity of bacteria, making it a target for antibiotic design. Kinetic isotope effects and computational studies have established a dissociative S(N)1 transition state for Escherichia coli MTAN, and transition state analogues resembling the transition state are powerful inhibitors of the enzyme [Singh, V., Lee, J. L., Núñez, S., Howell, P. L., and Schramm, V. L. (2005) Biochemistry 44, 11647-11659]. The sequence of MTAN from S. pneumoniae is 40% identical to that of E. coli MTAN, but S. pneumoniae MTAN exhibits remarkably distinct kinetic and inhibitory properties. 5'-Methylthio-Immucillin-A (MT-ImmA) is a transition state analogue resembling an early S(N)1 transition state. It is a weak inhibitor of S. pneumoniae MTAN with a K(i) of 1.0 microM. The X-ray structure of S. pneumoniae MTAN with MT-ImmA indicates a dimer with the methylthio group in a flexible hydrophobic pocket. Replacing the methyl group with phenyl (PhT-ImmA), tolyl (p-TolT-ImmA), or ethyl (EtT-ImmA) groups increases the affinity to give K(i) values of 335, 60, and 40 nM, respectively. DADMe-Immucillins are geometric and electrostatic mimics of a fully dissociated transition state and bind more tightly than Immucillins. MT-DADMe-Immucillin-A inhibits with a K(i) value of 24 nM, and replacing the 5'-methyl group with p-Cl-phenyl (p-Cl-PhT-DADMe-ImmA) gave a K(i) value of 0.36 nM. The inhibitory potential of DADMe-Immucillins relative to the Immucillins supports a fully dissociated transition state structure for S. pneumoniae MTAN. Comparison of active site contacts in the X-ray crystal structures of E. coli and S. pneumoniae MTAN with MT-ImmA would predict equal binding, yet most analogues bind 10(3)-10(4)-fold more tightly to the E. coli enzyme. Catalytic site efficiency is primarily responsible for this difference since k(cat)/K(m) for S. pneumoniae MTAN is decreased 845-fold relative to that of E. coli MTAN.


    Organizational Affiliation

    Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
5'-methylthioadenosine / S-adenosylhomocysteine nucleosidase
A, B, C, D, E, F
230Streptococcus pneumoniae (strain ATCC BAA-255 / R6)Mutation(s): 0 
Gene Names: pfs
EC: 3.2.2.9
Find proteins for Q8DQ16 (Streptococcus pneumoniae (strain ATCC BAA-255 / R6))
Go to UniProtKB:  Q8DQ16
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
MTM
Query on MTM

Download SDF File 
Download CCD File 
A, B, C, D, E, F
(3S,4R)-2-(4-AMINO-5H-PYRROLO[3,2-D]PYRIMIDIN-7-YL)-5-[(METHYLSULFANYL)METHYL]PYRROLIDINE-3,4-DIOL
(1S)-1-(9-DEAZAADENIN-9-YL)-1,4,5-TRIDEOXY-1,4-IMINO-5-METHYLTHIO-D-RIBITOL
C12 H19 N5 O2 S
YLCQGEBEQIBOOJ-BOFBLULFSA-N
 Ligand Interaction
External Ligand Annotations 
IDBinding Affinity (Sequence Identity %)
MTMKi: 1000 nM BINDINGMOAD
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.6 Å
  • R-Value Free: 0.211 
  • R-Value Work: 0.193 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 80.571α = 90.00
b = 138.958β = 117.92
c = 84.755γ = 90.00
Software Package:
Software NamePurpose
DENZOdata reduction
AMoREphasing
SCALEPACKdata scaling
CNSrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2006-04-25
    Type: Initial release
  • Version 1.1: 2008-04-30
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance
  • Version 1.3: 2018-01-24
    Type: Structure summary