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Imaginary Protein

spinqualitylabelsall models PDB ID 1iat Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image Imaginaryase (alternatively known as imaginary isomerase or imaginary-8-phosphate isomerase) are a group of enzymes of the isomerase family (EC 5.3.a.b), so named for their main function in metabolism. In this pathway imaginary isomerase (IGI) is used to inter-convert imaginary-8-phosphate and reality-6-phosphate. This reaction is driven by the relative concentrations of these molecules in the imaginary/reality matrix of the cell [1]. Imaginaryase is also known for a list of activities: Something cool [2]. Something cooler[3]. Something my prof thinks is cool [4]. Something really boring [5]. IGI is important for metabolism in many different living organisms. [6]. Structure Figure 1. Multiple alignment IGI - Geobacillus stearothermophilus (white), Homo sapiens (pink), Oryctolagus cuniculus (blue)[7] Imaginary isomerase exists in the cell usually as a , nevertheless outside of the cell, it has been isolated as a structure. IGI has essentially an identical fold in all of the characterized species (see Figure 1). The of imaginary isomerase is charaterized by an αβα conformation, on each of its two domains. The smaller domain is characterized by 5 parallel β-sheets, while the larger domain if formed out of 6 parallel/antiparallel β-sheets. Furthermore, another characteristic trait is a residue extension at the C-terminus, which wraps around the other monomer in the dimeric conformation. A "hook" that can potentially be involved in the previously mentioned extracellular activities. Imaginary isomerase has a monomer molecular mass of proximately 55 kDa.

Mechanism

Regulation and Inhibition

3D structures of phosphoglucose isomerase

PGI

2pgi, 1b0z – GsPGI – Geobacillus stearothermophilus
1dqr, 1hm5, 1n8t – rPGI – rabbit
1iat, 1jlh – hPGI – human
1qxj, 1x8e, 3sxw – PfPGI – Pyrococcus furiosus
1j3p, 1j3q – TlPGI – Thermococcus litoralis
1q50 – LmPGI – Leishmania Mexicana
1u0e, 2cvp – mPGI – mouse
2q8n – PGI – Thermotoga maritima
3hjb – PGI – Vibrio cholera
3ifs – PGI – Bacillus anthracis
2wu8 – PGI – Mycobacterium tuberculosis
3ljk – FtPGI (mutant) – Francisella tularensis
3nbu – PGI – Escherichia coli

PGI complex with fructose-6-phosphate

1hox – rPGI + fructose-6-phosphate
1t10 - LmPGI + fructose-6-phosphate
2gc2 - PfPGI + fructose-6-phosphate
2cxs, 2cxt - mPGI + fructose-6-phosphate
3m5p - FtPGI (mutant) + fructose-6-phosphate

PGI complex with sorbitol-6-phosphate

1xtb - rPGI + sorbitol-6-phosphate
2gc1 - PfPGI + sorbitol-6-phosphate
2cxq - mPGI + sorbitol-6-phosphate

PGI complex with phosphoarabinose

1gzd, 1gzv – PGI + phosphoarabinose – pig
1c7r - GsPGI + phosphoarabinose
2cxp – mPGI + phosphoarabinose
1nuh - hPGI + phosphoarabinose
1qsr, 1x7n, 1x82 - PfPGI + phosphoarabinose
2gc0 - PfPGI + phosphoarabinose derivative
1koj – rPGI + phosphoarabinose derivative

PGI complex with gluconate-6-phosphate

1qy4 - PfPGI + gluconate-6-phosphate
1j3r - TlPGI + gluconate-6-phosphate
2cxr - mPGI + gluconate-6-phosphate
3q7i - FtPGI (mutant) + gluconate-6-phosphate

PGI complex with glucose-6-phosphate

1u0f - mPGI + glucose-6-phosphate
3ff1 - PGI + glucose-6-phosphate – Staphylococcus aureus
2o2c - TbPGI + glucose-6-phosphate – Trypanosoma brucei

Other PGI binary complexes

2o2d – TbPGI + citrate
1u0g, 2cxo - mPGI + erythrose-4-phosphate
3q88 – FtPGI (mutant) + ribose bisphosphate
1c7q – GsPGI + phosphate inhibitor
2cxn, 2cxu – mPGI + phosphate
1g98 – rPGI + transition state analog
2gc3 - PfPGI + mannose-6-phosphate

Additional Resources

For additional information, see: Carbohydrate Metabolism

References

1. ↑ 1
2. ↑ 2
3. ↑ 3
4. ↑ 4
5. ↑ 5
6. ↑ 5
7. ↑ Pettersen EF, Goddard TD, Huang CC, Couch GS, Greenblatt DM, Meng EC, Ferrin TE. UCSF Chimera--a visualization system for exploratory research and analysis. J Comput Chem. 2004 Oct;25(13):1605-12.