In addition, a switch between monomeric and tetrameric/multimeric states has been observed recently.
Ulf Dettmer 2018, 'Rationally Designed Variants of α-Synuclein Illuminate Its in vivo Structural Propertiesin Health and Disease', Frontiers in Neurosciencehttps://www.frontiersin.org/article/10.3389/fnins.2018.00623/full. Retrieved from DOAJ CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)
The asymmetric unit contained two tetrameric hemoglobin molecules.
Noriko Inoguchi, Nobuhiro Mizuno, Seiki Baba, Takashi Kumasaka, Chandrasekhar Natarajan,Jay F Storz, Hideaki Moriyama 2017, 'Alteration of the α1β2/α2β1 subunit interface contributes to the increased hemoglobin-oxygenaffinity of high-altitude deer mice.', PLoS ONEhttp://europepmc.org/articles/PMC5376325?pdf=render. Retrieved from PLOS CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)
Dimeric and tetrameric peptides showed higher antibacterial activity in both bacteria strains than linear peptides.
Yerly Vargas Casanova, Jorge Antonio Rodríguez Guerra, Yadi Adriana Umaña Pérez, AuraLucía Leal Castro, Giovanni Almanzar Reina, Javier Eduardo García Castañeda, ZulyJenny Rivera Monroy 2017, 'Antibacterial Synthetic Peptides Derived from Bovine Lactoferricin Exhibit CytotoxicEffect against MDA-MB-468 and MDA-MB-231 Breast Cancer Cell Lines', Moleculeshttps://www.mdpi.com/1420-3049/22/10/1641. Retrieved from DOAJ CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)
A novel form of tetrameric streptavidin has been engineered to have reversible biotin binding capability.
Valerie J O'Sullivan, Isabelle Barrette-Ng, Eric Hommema, Greg T Hermanson, Mark Schofield,Sau-Ching Wu, Claudia Honetschlaeger, Kenneth K-S Ng, Sui-Lam Wong 2012, 'Development of a tetrameric streptavidin mutein with reversible biotin binding capability:engineering a mobile loop as an exit door for biotin.', PLoS ONEhttp://europepmc.org/articles/PMC3334968?pdf=render. Retrieved from PLOS CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)
These receptors are tetrameric ion channels composed of a family of related subunits.
Ashok eKumar 2015, 'NMDA receptor function during senescence: implication on cognitive performance', Frontiers in Neurosciencehttp://journal.frontiersin.org/Journal/10.3389/fnins.2015.00473/full. Retrieved from DOAJ CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)
The dimers tend to self-associate to a tetrameric form at higher protein concentrations.
Vojtěch Sedláček, Tomáš Klumpler, Jaromír Marek, Igor Kučera 2014, 'The Structural and Functional Basis of Catalysis Mediated by NAD(P)H:acceptor Oxidoreductase(FerB) of Paracoccus denitrificans', PLoS ONE10.1371/journal.pone.0096262. Retrieved from PLOS CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)
There are hydrogen-bonding interactions between water molecules, which result in cyclic tetrameric water clusters.
Mahnaz Adinehloo, Mahboubeh A. Sharif, Masoumeh Tabatabaee, Hossein Aghabozorg 2010, '2-Amino-4-methylpyridinium 6-carboxypyridine-2-carboxylate sesquihydrate', Acta Crystallographica Section Ehttp://scripts.iucr.org/cgi-bin/paper?S1600536810046866. Retrieved from DOAJ CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)
Oligomeric forms were observed with both enzymes in addition to the tetrameric and dimeric forms.
Hanan Sharif, Jagarlamudi Kiran, Liya Wang, Ellen He, Staffan Eriksson 2012, 'Quaternary structures of recombinant, cellular, and serum forms of Thymidine Kinase1 from dogs and humans', BMC Biochemistryhttp://www.biomedcentral.com/1471-2091/13/12. Retrieved from DOAJ CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)
These reveal a striking contrast between the dynamics of tetrameric and dimeric forms.
C F Reboul, B T Porebski, M D W Griffin, R C J Dobson, M A Perugini, J A Gerrard,A M Buckle 2012, 'Structural and dynamic requirements for optimal activity of the essential bacterialenzyme dihydrodipicolinate synthase.', PLoS Computational Biologyhttp://europepmc.org/articles/PMC3369909?pdf=render. Retrieved from PLOS CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)