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Table 1 Mutagenesis studies on CDF members

From: Phylogenetic and functional analysis of the Cation Diffusion Facilitator (CDF) family: improved signature and prediction of substrate specificity

  Prokaryotic members Eukaryotic member
  RmCzcD EcZitB EcFieF PtdMTP1
Topological position AA substitution Phenotype AA substitution Phenotype AA substitution Phenotype AA substitution Phenotype
N ter        C30S Partially activee
N ter        C35S No functione
N ter        C64S Partially activee
N ter H5R Partially activea       
N ter H7R No functiona       
N ter H9R Partially activea       
TMD I E31D Partially activea E35D Partially activeb     
TMD I    E35A Partially activeb     
TMD I E31K No functiona       
TMD II    D50E Partially activea     
TMD II    D50A No functiona    D86A No functionf
TMD II      D45C Wild type c   
TMD II H49R Not expressed a H53R No function a    H89K No function f
TMD II H49A No function a      H89A No function f
TMD II M5OL Hypersensitivea M54L Partially activea     
TMD II      D49C Wild type c   
TMD II D53E Hypersensitive a       
TMD II D53A Hypersensitive a D57A No function a D49A No function c D93A No function f
TMD II D53N Hypersensitivea       
TMDs II-III loop        G118A No functione
TMD IV    N135A No functiona     
TMD V      H153C Partially active c   
TMD V E154D No function a H159E No function a    H260D No function e
TMD V E154N No function a H159R No function a     
TMD V      D157C Partially active d   
TMD V D158E No function a D163E No function a    D264E No function e
TMD V D158A No function a D163A No function a D157A No function d D264A No function e
TMD V    S167A No functiona     
    W182L Partially activea     
TMD VI D181A Partially activea D186A No functiona    D288A No functione
TMD VI D181E Hypersensitivea D186E Partially activea    D288E No functione
TMD VI D181N Hypersensitivea       
C ter        C291S Wild typee
C ter    E214A No functiona     
C ter H237R No functiona       
C ter H251A Partially activea       
C ter    W245L Partially activea     
C ter    G248T Partially activeb     
C ter        C357S Wild typee
C ter H280A No functiona       
C ter H298A No functiona       
C ter C290S Hypersensitivea C294S Wild typea     
  1. The results of site-directed mutagenesis analyses carried out on four CDF transporters ([14, 23, 29-31] and present study) are reported with the corresponding topological position. RmCzcD: Zn-CDF from C. metallidurans; EcZitB: Zn-CDF from E. coli; EcFieF: Fe/Zn-CDF from E. coli; PtdMTP1: Zn-CDF from P. trichocarpa × deltoides. "no function": the amino acid substitution led to the loss of any detectable function in the complementation test, comparable with the empty vector; "hypersensitive": the amino acid substitution resulted in a more sensitive phenotype, compared with the empty vector-transformed cells; "partially active": the phenotype is intermediate between the empty vector- and the wild type gene-transformed cells. EcFieF metal coordination residues [31] and the corresponding amino acids in the other transporters are in bold. References: a, [29]; b, [30]; c, [31]; d, [14]; e, this study; f, [23].