Part:BBa_K3736000

STATH(Statherin)
A protein that promotes tooth remineralization and repairs decalcified enamel.
Statherin is a protein in humans that is encoded by the STATH gene. It prevents the precipitation of calcium phosphate in saliva, maintaining a high calcium level in saliva available for remineralisation of tooth enamel and high phosphate levels for buffering.

Calcium Attachment Test

To test whether the STATH expressed by DenTeeth had the function, we decided to detect the calcium ions concentration change with the STATH property of binding to the surface of hydroxyapatite (HA), preventing the calcium ion from attaching to HA. Due to HA being the main component of enamel in teeth, we want to use HA to simulate the oral condition. However, the calcium ion concentration change was too small to detect, and no vendor could provide us HA in time, resulting from the impact of Covid-19.

After the consultation with prof. Hsiao-Ching, Lee, we came up with a replacement plan, observing the attachment of calcium ions on the carbon rod surface. Carbon rods are processed to have small, low-volume pores that increase the surface area available for adsorption. We expected that both STATH and calcium could adsorb on the surface of carbon rods, so we designed a test to observe the surface of carbon rods soaked in different solutions under the microscope.

We made four solutions configured to calcium ions saturated solutions by the calcium chloride solution, ddH₂O, LB broth, DenTeeth, and E. coli with pET32A, in the tubes with the carbon rods stuck inside. After putting them into a 0°C refrigerator for 12 hours, the solutions would become calcium ions supersaturated solutions. In the DenTeeth, STATH would bind onto the surface of the carbon rod, preventing the calcium ions from binding onto it.

As for the precipitation on the bottom of tubes was the debris of bacteria, which was died of the broken cell membrane caused by the high concentration of calcium chloride solution.

                   role="img" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512">
                   <path fill="currentColor"
                       d="M8 256C8 119 119 8 256 8s248 111 248 248-111 248-248 248S8 393 8 256zm143.6 28.9l72.4-75.5V392c0 13.3 10.7 24 24 24h16c13.3 0 24-10.7 24-24V209.4l72.4 75.5c9.3 9.7 24.8 9.9 34.3.4l10.9-11c9.4-9.4 9.4-24.6 0-33.9L273 107.7c-9.4-9.4-24.6-9.4-33.9 0L106.3 240.4c-9.4 9.4-9.4 24.6 0 33.9l10.9 11c9.6 9.5 25.1 9.3 34.4-.4z">
                   </path>

</svg>Figure 4. The calcium ions saturated solutions.( A. ddH₂O, B. LB broth, C. DenTeeth, D. E. coli with pET32A)</i>

The result in the following figure showed that the surface of the carbon rod taken out of the DenTeeth was matte compared with that in other solutions. We presumed that the result was due to the protective layer on the surface formed by the STATH that would prevent the liquid from attachment.

               <img class="images" src="https://2021.igem.org/wiki/images/1/1f/T--NCTU_Formosa--stath_stick.png?fbclid=IwAR0HLuoVlPFbls-TRxdvI79b5pAt5ogbSGjZQ1lukGdXQvJeKBB0tPJ4uw4">

                   role="img" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512">
                   <path fill="currentColor"
                       d="M8 256C8 119 119 8 256 8s248 111 248 248-111 248-248 248S8 393 8 256zm143.6 28.9l72.4-75.5V392c0 13.3 10.7 24 24 24h16c13.3 0 24-10.7 24-24V209.4l72.4 75.5c9.3 9.7 24.8 9.9 34.3.4l10.9-11c9.4-9.4 9.4-24.6 0-33.9L273 107.7c-9.4-9.4-24.6-9.4-33.9 0L106.3 240.4c-9.4 9.4-9.4 24.6 0 33.9l10.9 11c9.6 9.5 25.1 9.3 34.4-.4z">
                   </path>

</svg>Figure 5. The carbon rods took out from calcium ions saturated solutions.( A. ddH₂O, B. Original ( did not soaked in the any solution), C. LB broth, D. DenTeeth, E. E. coli with pET32A)</i>

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]