The Protein Folding Database
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  Statistics
Version: 2.2
Last Update: 8-Jun-2007
Entries: 296
Proteins: 70
Families: 53
Species: 30
ϕ values: 230 (5 proteins)
Locations of visitors to this page
  Latest Additions
ACBP (3 WT)
FRB (6 WT)
CI2 (3 WT, 202 mutants)
HPr (1 WT, 4 mutants)
Im7 (1 WT)
En-HD (1 WT)
Im9 (2 WT)
Abp1 SH3 (1 WT)
CheW (1 WT)
U1A (1 WT)
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Fulton et al (2005) Nucleic Acids Res. 33:D279-283  |  Fulton et al (2007) Nucleic Acids Res. 35:D304-307 About PFD | Help | Glossary

Folding Data
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Note: A field with its data listed as "ND" denotes there is no data for that field.
[Measurement ID: 16] contact us to make corrections & updates to this data

Expand   Compare Data
compare with other measurements for this protein (1)compare with other measurements for proteins in this SCOP Family (3)

Expand   Protein Data
Protein Name E colicin binding Immunity Protein 9 (ImmE9) (Im9)
Oligomeric State Monomer
Folding Mechanism Framework
Intermediates 0
Phi Pattern No phi value analysis
SCOP Class Alpha   |   goto SCOP
SCOP Family Colicin E immunity proteins   |   goto SCOP

Expand   Construct Data
Species E. coli (Escherichia coli)

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Sequence MEHHHHHHELKHSISDYTEAEFLQLVTTICNADTSSEEELVKLVTHFEEM
TEHPSGSDLIYYPKEGDDDSPSGIVNTVKQWRAANGKSGFKQG

Blast PFD  |  Blast NCBI NR
Length 94
Molecular Weight 10516.5Da
Fusion N-terminal hexahistidine
PDB ID 1IMQ   |   goto PDB  
PDB Resolution NMR
Chain Any chain
Residues 2 - 86
SCOP ID 47352   |   goto SCOP
UniProt ID IMM9_ECOLI   |   goto UniProt
Relative Contact Order 11.06

Expand   Publication Data
Publication Maxwell KL et al (2005) Protein folding: defining a "standard" set of experimental conditions and a preliminary kinetic data set of two-state proteins., Protein Science 14, 602-616  goto pubmed
Data type in publication Equilibrium & Kinetic   |   view other data in this publication

Expand   Graphical Analysis Data
Chevron Plot chevron plot for measurement 16
unfolding & refolding data
ln(kuH2O)
(s-1)		 ln(kfH2O)
(s-1)		 m‡-N
(kJ mol-1 M-1)		 m‡-D
(kJ mol-1 M-1)
-1.87 ± 0.05 7.33 ± 0.02 0.26 ± 0.02 -4.53 ± 0.01
Notes on Chevron Plot Calculating
Contact Order Plot Data Acyl Coenzyme A Binding Protein Hypothetical protein YjbJ from Escherichia coli E colicin binding Immunity Protein 7 (ImmE7*) E colicin binding Immunity Protein 9 (ImmE9) Lambda C1 repressor, DNA-binding domain E colicin binding Immunity Protein 9 (ImmE9) Acyl Coenzyme A Binding Protein Acyl Coenzyme A Binding Protein Internalin B, C-terminal domain Apo-azurin Chemotaxis protein CheW Fyn proto-oncogene tyrosine kinase, SH3 domain Alpha-Spectrin SH3 Domain c-src tyrosine kinase SH3 Domain Actin binding protein 1 SH3 domain Activation Domain Of Human Procarboxypeptidase A2 Chymotrypsin Inhibitor 2 Ribosomal protein L9 C-domain FK-506 binding protein Ribosomal protein L23 Acylphosphatase Ribosomal protein L9 N-domain Immunoglobulin-binding protein G Immunoglobulin light chain-binding domain of protein L c-Raf1 RBD Ribosomal protein S6 c-src tyrosine kinase SH2 domain Spliceosomal U1A protein Ubiquitin FK-506 binding protein Chymotrypsin Inhibitor 2 Chymotrypsin Inhibitor 2
generated contact order graph

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To view more data on a SCOP Class click on it's name in the legend.
Note: Mutant measurements do not have their data plotted on this graph, instead the data from wildtype is marked in red.

view notes on contact order

Expand   Equilibrium Data & Methods
Equilibrium Data
[Denaturant] Minimum
(M)		 [Denaturant] 50%
(M)		 mD-N (m)
(kJ mol-1 M-1)		 ∆GD-N (m)
(kJ mol-1)
ND ND -4.4 ± 0.1 20.9 ± 0.6
Probe Far-UV Circular Dichroism  what is this?
Pertubation Denaturant  what is this?
Technique Urea
Instrument Jasco J-715 Spectrophotometer
Temperature 298K
pH 7
Buffer 0.05M TrisHCl
Protein Concentration 0.02M

Expand   Kinetic Data & Methods
Kinetic Unfolding Data
[Denaturant] Minimum
(M)		 [Denaturant] Maximum
(M)		 ku
(s-1)		 lnku
(s-1)		 mu
(M-1)		 m‡-N
(kJ mol-1 M-1)
5.25 8 0.15412 ± 0.00019 (0M) -1.87 ± 0.05 (0M) ND 0.26 ± 0.02
Kinetic Folding Data
[Denaturant] Minimum
(M)		 [Denaturant] Maximum
(M)		 kfH2O
(s-1)		 ln(kfH2O)
(s-1)		 mf
(M-1)		 m‡-D
(kJ mol-1 M-1)
1 5 1525.38 ± 0.31 7.33 ± 0.02 ND -4.53 ± 0.01
Probe Trp Fluorescence  what is this?
Pertubation Denaturant  what is this?
Technique Urea
Instrument Applied Photophysics SF.18MV Stopped-flow fluorimeter
Temperature 298K
pH 7
Buffer 0.05M TrisHCl
Protein Concentration 0.02M
Unfolding Fit Linear
Refolding Fit Linear

Expand   Notes & Comments on this measurement
Measurement Notes
Protein Notes High-resolution structure shows that the protein adopts a distorted, antiparallel four-helical structure. The small size of this protein, lack of disulphide bonds, prosthetic groups and cis-Xaa prolyl peptide bonds in the native state, makes the immunity protein ideal for folding studies. Moreover, the presence of a unique conserved tryptophan residue (W74) which is highly quenched in the native state and their all a-helical topology, make these proteins easily amenable to analysis by fuorescence and far-UV CD spectroscopy.
Construct Notes CO calculated using PDB entry 1FR2 equals 9.4. PDB file in Maxwell et al 2005 is 1IMQ. CO calculated using PDB entry 1IMQ equals 10.4.
Equilibrium Notes Im7* and Im9*. Maxwell et al 2005. These homologs were prepared and their folding and unfolding kinetics and thermodynamics were measured as previously described (Capaldi et al., 2002; Friel et al., 2003) save under the conditions described here. Each protein contains the amino-terminal tag ME(H)6, which is denoted by the asterisk (i.e. Im7* and Im9*). Under the conditions employed the folding of both proteins appear two-state. A mild non-linearity in the urea dependence of ln(ku), which was previously noted (Ferguson et al., 1999) in the folding of Im7, was also observed under these consensus conditions. (CTF, SER). From PFD1: Jasco PTC-348W peltier system for temperature regulation. Measurements taken at 225nm (1nm bandwidth) in a 1 mm pathlength cuvette. Protein concentration 20microM. Friel et al 2003: Im9* is an N-terminally His-tagged version of Im9; the His-tag added is MEHHHHHHE2, where E2 is the second residue of the wild-type sequence
Kinetic Notes Im7* and Im9*. Maxwell et al 2005. These homologs were prepared and their folding and unfolding kinetics and thermodynamics were measured as previously described (Capaldi et al., 2002; Friel et al., 2003) save under the conditions described here. Each protein contains the amino-terminal tag ME(H)6, which is denoted by the asterisk (i.e. Im7* and Im9*). Under the conditions employed the folding of both proteins appear two-state. A mild non-linearity in the urea dependence of ln(ku), which was previously noted (Ferguson et al., 1999) in the folding of Im7, was also observed under these consensus conditions. (CTF, SER). Friel et al 2003: Fluorescence of the single tryptophan residue (W74) was excited at 280nm with a bandwidth of 10nm and the emitted fluorescence monitored at >320nm. Folding was initiated by mixing 50uM protein and 8.00M urea in a 1:10 ratio with the same buffer lacking protein, containing various concentrations of urea. Unfolding was measured in the same way but the initial protein solution did not contain urea. Folding and unfolding were measured between 0.75M and 8.00M final urea concentration in 0.25M increments. The folding and unfolding kinetics were fitted using the software provided with the stopped-flow instrument. All the refolding time-courses were well described by a double-exponential function. The slower, second phase, which in all cases was <10% of the total amplitude, has previously been attributed to proline-limited folding events and is not considered further here. All unfolding data were well described by a single-exponential function.
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