Part:BBa_K1033906

tsPurple, purple chromoprotein

This chromoprotein (also known as TinselPurple) naturally exhibits strong purple color when expressed.

Usage and Biology

This part is useful as a reporter.

iGEM2013 Uppsala: The images above show E coli constitutively expressing the chromoproteins amilCP BBa_K592009 and tsPurple BBa_K1033906 from the high copy plasmid pSB1C3 from the promoters J23116 and J23110.

Sequence and Features

Assembly Compatibility:

10
COMPATIBLE WITH RFC[10]
12
COMPATIBLE WITH RFC[12]
21
COMPATIBLE WITH RFC[21]
23
COMPATIBLE WITH RFC[23]
25
COMPATIBLE WITH RFC[25]
1000
COMPATIBLE WITH RFC[1000]

Structure and SWISS MODEL Homology Modelling Report

(The following information has been contributed by SVCE_Chennai 2016)

The following sections give a detailed information on this chromoprotein done by its in silico analysis.

3D Structure

Cartoon representation of tsPurple.

QMEANnorm = 0.02
Cβ = -0.91
All Atom = 0.52
Solvation = -1.19
Torsion = 0.32

The best match during structure prediction.

Template	Seq. Identity	Oligo-state	Found by	Method	Resolution	Seq Similarity	Range	Coverage	Description
4ohs.1.A	86.61	homotetramer	HHblits	X-Ray	2.19Å	0.58	2 - 222	0.98	FAR-RED FLUORESCENT PROTEIN AQ143

What about Ligands?

Ligand	Added to Model	Description
CL	✕ - Not biologically relevant.	CHLORIDE ION
CL	✕ - Not biologically relevant.	CHLORIDE ION
CL	✕ - Not biologically relevant.	CHLORIDE ION

Plot 1

Plot 2

Plot 3

Plot 1

The area built by the circles colored in different shades of grey in the plot on the left hand side represent the QMEAN scores of the reference structures from the PDB. The model's QMEAN score is compared to the scores obtain for experimental structures of similar size (model size +/- 10%) and a Z-score is calculated. A Z-score (or standard score) is a score which is normalised to mean 0 and standard deviation 1. Thus the QMEAN Z-score directly indicates how many standard deviations the model's QMEAN score differs from expected values for experimental structures. In analogy, Z-scores are calculated for all four statistical potential terms as well as the agreement terms being part of the QMEAN score.

Plot 2

The plot in the middle shows the density plot (based on the QMEAN score) of all reference models used in the Z-score calculation. The location of the query model with respect to the background distribution is marked in red. This plot basically is a "projection" of the first plot for the given protein size. The number of reference models used in the calculation is shown at the bottom of the plot.

Plot 3

The analysis of these Z-scores of the individual terms can help identifying the geometrical features responsible for an observed large negative QMEAN Z-score. Models of low quality are expected to have strongly negative Z-scores for QMEAN but also for most of the contributing terms. Large negative values correspond to red regions in the color gradient. "Good structures" are expected to have all sliders in the light red to blue region.”

Ramachandran Plot- SWISS MODEL Workspace

(The following information has been contributed by SVCE_Chennai 2016)

File:Ramaplot tspurple.pdf

A score of 93.3% in the most favoured regions as seen in the Ramachandran plot shows that the above predicted model of Tinsel Purple chromoprotein is a very good prediction.

ProtParam Results

(The following information has been contributed by SVCE_Chennai 2016)

Number of amino acids: 228
Molecular weight: 25546.26
Theoretical pI: 6.65
Total number of negatively charged residues (Asp + Glu): 27
Total number of positively charged residues (Arg + Lys): 26

Atomic composition:

Carbon (C) - 1134
Hydrogen (H) - 1747
Nitrogen (N) - 303
Oxygen (O) - 334
Sulfur (S) - 18

Formula: C₁₁₃₄H₁₇₄₇N₃₀₃O₃₃₄S₁₈
Total number of atoms: 3536

Extinction coefficients:

Extinction coefficients are in units of M^-1 cm^-1, at 280 nm measured in water.

Ext. coefficient : 24910
Abs 0.1% (=1 g/l): 0.975, assuming all pairs of Cys residues form cystines

Ext. coefficient : 24410
Abs 0.1% (=1 g/l): 0.956, assuming all Cys residues are reduced

Estimated half-life:

The N-terminal of the sequence considered is M (Met).

The estimated half-life is: 30 hours (mammalian reticulocytes, in vitro).
>20 hours (yeast, in vivo).
>10 hours (Escherichia coli, in vivo).

Instability index:

The instability index (II) is computed to be 31.19
This classifies the protein as stable.

Aliphatic index: 61.97

Grand average of hydropathicity (GRAVY): -0.395