Unstructured Proteins in Biological Structures: The Case of Human Teeth from a Protein Chemist's Perspective

Abstract

Proteins are the biomacromolecules that work downstream to genes in every living system. It is these protein molecules that are responsible for a plethora of functions in our body, ranging from building skeleton tissues to transmitting signal from one place to others. There was a period when biologists have the view that for a protein to function, the structure is of supreme importance. Nevertheless, this structure‐function paradigm is fairly obeyed by most of the proteins, if not all of them. Last two decades have witnessed the increased reports of proteins that do not have a stable three‐dimensional structure but are very much indispensable for the cellular and biological activities. These unstructured proteins are now known as “Intrinsically disordered proteins” (IDPs). Interestingly, these IDPs function not only in isolation (e.g. transcription factors) but helps in the formation of hard tissues like teeth, bone, and mollusks shell, by governing a process called biomineralization. Biomineralization is the process by which living organisms produce minerals, often to harden or stiffen existing tissues. Such tissues are called mineralized tissues.We have isolated total protein extracts from a healthy molar, premolar, canine and incisor teeth. We studied their protein secondary structural characteristics using various biophysical techniques. We have also investigated the effects of these protein extracts on mineralization of calcium phosphate through in vitro biomineralization assay followed by size‐based measurement analysis via Nanoparticle tracking analysis (NTA). The biophysical studies confirmed the presence of IDPs in the majority within these protein extracts. Moreover, these extracts were shown to elevate calcium phosphate biomineralization in a time‐dependent manner. This is the first time the effect of the whole protein extract was taken into account which in our view more closely imitates the in vivo process of tooth biomineralization. Furthermore, we also evaluated the differential proteome profile of the individual type of human teeth through Mass spectroscopy‐based method. The comparative qualitative and quantitative data of proteins from these different human teeth were obtained. The implication of these results will be discussed.Support or Funding InformationThere was no support or funding from any organizationThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.