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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/01/06 12:00:23」(JST)

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The heterotetrameric molecule haemoglobin, made up of four subunits of two different types (coloured red and blue.)

A heterotetramer is protein containing four non-covalently bound subunits, wherein the subunits are not all identical.^[1] A homotetramer contains four identical subunits.^[2]

Examples include haemoglobin (pictured), the NMDA receptor, some aquaporins,^[3] some AMPA receptors, as well as some enzymes.^[4]

Purification of heterotetramers

Ion-exchange chromatography is useful for isolating specific heterotetrameric protein assemblies, allowing purification of specific complexes according to both the number and the position of charged peptide tags.^[5]^[6] Nickel affinity chromatography may also be employed for heterotetramer purification.^[7]

References

^ "GO term: protein heterotetramerization". YeastGenome. Retrieved 14 May 2011.
^ "GO term: protein homotetramerization". YeastGenome. Retrieved 14 May 2011.
^ Neely, John D.; Christensen, Birgitte M.; Nielsen, Søren; Agre, Peter (1 August 1999). "Heterotetrameric Composition of Aquaporin-4 Water Channels". Biochemistry 38 (34): 11156–63. doi:10.1021/bi990941s. PMID 10460172.
^ Chang, T.-H.; Hsieh, F.-L.; Ko, T.-P.; Teng, K.-H.; Liang, P.-H.; Wang, A. H.-J. (5 February 2010). "Structure of a Heterotetrameric Geranyl Pyrophosphate Synthase from Mint (Mentha piperita) Reveals Intersubunit Regulation". Plant Cell 22 (2): 454–467. doi:10.1105/tpc.109.071738. PMC 2845413. PMID 20139160.
^ Sakash, J.B.; Kantrowitz, E.R. (2000). "The contribution of individual interchain interactions to the stabilization of the T and R states of Escherichia coli aspartate transcarbamoylase.". J Biol Chem 275 (37): 28701–7. doi:10.1074/jbc.M005079200. PMID 10875936.
^ Fairhead, M. (2013). "Plug-and-Play Pairing via Defined Divalent Streptavidins.". J Mol Biol 426 (1): 199–214. doi:10.1016/j.jmb.2013.09.016. PMID 24056174.
^ Howarth, Mark; Chinnapen, Daniel J-F; Gerrow, Kimberly; Dorrestein, Pieter C; Grandy, Melanie R; Kelleher, Neil L; El-Husseini, Alaa; Ting, Alice Y (2006). "A monovalent streptavidin with a single femtomolar biotin binding site". Nature Methods 3 (4): 267–73. doi:10.1038/nmeth861. PMC 2576293. PMID 16554831.

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English Journal

Escherichia coli LysU is a potential surrogate for human lysyl tRNA synthetase in interactions with the C-terminal domain of HIV-1 capsid protein.

Boonyalai N, Pullen JR, Abdul Wahab MF, Wright M, Miller AD.SourceImperial College Genetic Therapies Centre, Department of Chemistry, Flowers Building, Armstrong Road, Imperial College London, London SW7 2AZ, UK. a.miller07@btinternet.com.
Organic & biomolecular chemistry.Org Biomol Chem.2013 Jan 28;11(4):612-20. doi: 10.1039/c2ob26499d. Epub 2012 Dec 4.
Human lysyl-tRNA synthetase (hLysRS) is known to interact directly with human immunodeficiency virus type-1 (HIV-1) GagPol polyproteins, and both hLysRS with tRNA(Lys3) are selectively packaged into emerging HIV-1 viral particles. This packaging process appears to be mediated by contact between the
PMID 23208549

Assembly Of The SLIP1-SLBP Complex On Histone mRNA Requires Heterodimerization And Sequential Binding Of SLBP Followed By SLIP1.

Bansal N, Zhang M, Bhaskar A, Itotia P, Lee E, Shlyakhtenko LS, Lam TT, Fritz A, Berezney R, Lyubchenko YL, Stafford WF, Thapar R.AbstractThe SLIP1-SLBP complex activates translation of replication-dependent histone mRNAs. In this report, we describe how the activity of the SLIP1-SLBP complex is modulated by phosphorylation and oligomerization. Biophysical characterization of the free proteins shows that whereas SLIP1 is a homodimer that does not bind RNA, human SLBP is an intrinsically disordered protein that is phosphorylated at 23 Ser/Thr sites when expressed in a eukaryotic expression system such as baculovirus. The bacterially expressed unphosphorylated SLBP-SLBP complex forms a 2:2 high affinity (KD < 0.9 nM) heterotetramer that is also incapable of binding histone mRNA. In contrast, phosphorylated SLBP from baculovirus has weak affinity (KD ~3 μM) for SLIP1. Sequential binding of phosphorylated SLBP to the histone mRNA stem-loop, followed by association with SLIP1 is required to form an "active" ternary complex. Phosphorylation of SLBP at Thr171 promotes dissociation of the heterotetramer to the SLIP1-SLBP heterodimer. Using alanine scanning mutagenesis we demonstrate that the binding site on SLIP1 for SLBP lies close to the dimer interface. A single point mutant near the SLIP1 homodimer interface abolished interaction with SLBP in vitro and reduced histone mRNA abundance in vivo. On the basis of these biophysical studies, we propose that oligomerization and SLBP phosphorylation may regulate the SLBP-SLIP1 complex in vivo. SLIP1 may act to sequester SLBP in vivo protecting it from proteolytic degradation as an inactive hetero-tetramer, or alternatively, formation of the SLIP1-SLBP hetero-tetramer may facilitate removal of SLBP from the histone mRNA prior to histone mRNA degradation.
Biochemistry.Biochemistry.2013 Jan 3. [Epub ahead of print]
The SLIP1-SLBP complex activates translation of replication-dependent histone mRNAs. In this report, we describe how the activity of the SLIP1-SLBP complex is modulated by phosphorylation and oligomerization. Biophysical characterization of the free proteins shows that whereas SLIP1 is a homodimer
PMID 23286197

Structure of the type VI effector-immunity complex (Tae4-Tai4) provides novel insights into the inhibition mechanism of the effector by its immunity protein.

Zhang H, Zhang H, Gao ZQ, Wang WJ, Liu GF, Xu JH, Su XD, Dong YH.SourceChinese Academy of Science, China;
The Journal of biological chemistry.J Biol Chem.2013 Jan 3. [Epub ahead of print]
The type VI secretion system (T6SS), a multi-subunit needle-like apparatus, has been recently found to play a role in interspecies interactions. The Gram-negative bacteria harboring T6SS (donor) deliver the effectors into their neighboring cells (recipient) to kill them. Meanwhile, the cognate immun
PMID 23288853