"Identify the molecule" league #7. Prize: knowledge + 100 STEM + 200 TMN

This contest is an attempt to promote scientific knowledge among community in a fun and interesting way with the help of molecules.
Some people like to travel around the world and tell others stories about what happens outside of our organisms/cells in other countries.
And with “Identify the molecule” contest you can try to travel inside our own organism/cells and cells of the organisms around us.

For more information about this contest read "Identify the molecule" contest. Upgrade (the league, additional bonuses and more) post.

Prizes/bonuses:

The prize here is

1. knowledge

facts, information, and skills acquired through experience or education; the theoretical or practical understanding of a subject
[Oxford Dictionary of English, 3rd Edition, Oxford University Press, 2010]

That understanding of our own organism and organisms around us is the real prize in the case of this contest. No matter what happens (whether or not you get 100 STEM), you can win (can acquire the knowledge by investigating different sources of information, remembering and using it to your advantage in the future).

2. 100 STEM

STEMGeeks is a community focused on STEM topics rewarding engagement with STEM tokens. STEMGeeks is powered by the Steem blockchain with it's own distribution model for STEM tokens in addition to the potential STEEM tokens.
STEM stands for Science, Technology, Engineering, Math and includes a wide range of science and technology topics.
[source]

3. 200 TMN

Aside from STEM I’d like to add TMN tokens.
For the uninitiated, TMN is the token of TranslateMe project (it’s about combining blockchain technology (NEO in this case) with translation industry).
The reason I’m going to add this token for the prize pool of this contest is not only because I have them, but because this contest is quite scientific, and TranslateMe project might help to solve the “lost” science problem.
For more on this you can read my post regarding TranslateMe (TranslateMe (or Decentralization meets Translation industry). Part 2. The “missing puzzle piece” of scientific ecosystem. General overview) (and other posts of that series).

For more information on crypto-bonuses for this league, please refer to "Identify the molecule" contest. Upgrade (the league, additional bonuses and more) post.

Consider these tokens as a bonus.

Images and text are the clues for you to guess a riddle (the name of the molecule in this case).

Note that

a) even though this contest is called “Identify the molecule”,
-> molecule (singular)
sometimes it’s not just a molecule which is responsible for a specific function, but rather a complex of molecules.
Example:
cytochrome c oxidase (Complex IV)

is a large transmembrane protein complex… It is the last enzyme in the respiratory electron transport chain of cells located in the membrane.
source

b) some molecules/complexes have different names. For example, other names for cytochrome c oxidase (example above) are

Complex IV (mitochondrial electron transport).
Cytochrome a3.
Cytochrome aa3.
Cytochrome oxidase.
Warburg's respiratory enzyme.
source

Any of those names would be a valid entry.

c) Some almost identical molecules are grouped into classes / groups / families.
Example:
Helicases are divided into 6 groups. RecD and Dda molecules belong to helicases group (Superfamily 1 (SF1)). In this case you would need to guess only the name of the group –> Helicase/ Helicases.

d) Some proteins can have different forms – isoforms.
Example:
There’re trypsin 1 and trypsin 2. In this case you would need to guess only the general name – trypsin.

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Important

In order to get TMN, you’ll need to have NEO-wallet and provide me your public NEO-address.
If you don’t have it yet, don’t worry, I published a post on how/where to get it (O3 wallet).
Note that NEO-addresses provided by exchanges will not work in this case (+ it's safer NOT to keep your funds on exchanges). It's highly recommended to get O3 wallet.

If there’re no winners on any stage, the prize will be distributed equally among all users who provided any guesses for molecules.

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Riddle

This molecule is located in membranes and assembles with other monomers into tetramers (and each monomer functions independently).

It serves as a transporter (membrane transport protein)

It’s the key player of the system, which helps animals to concentrate urine [1]

It can be found in all kingdoms of life [2]

One scientist was awarded the Nobel Prize for the discovery of this molecule more than 15 years ago [3]

(Cartoon representation. The images were created by me with the help of PyMol - open source tool for molecular visualization/exploration.PDB-file was obtained from PDB)

Here’s the data showing where (in what human normal tissues) the gene of this molecule is expressed the most:

(in other words, those are the places where the molecule is present in abundance)
And here’s the data showing where (in what human normal tissues) the gene of this molecule is expressed the least:

(in other words, those are the places where the amount of this molecule is the lowest).

(Cartoon representation. The images were created by me with the help of PyMol - open source tool for molecular visualization/exploration. PDB-file was obtained from PDB)

Once this molecule was “The molecule of the month” on PDB (Protein Data Bank).

The RCSB PDB Molecule of the Month by David S. Goodsell (RCSB PDB-Rutgers and The Scripps Research Institute) presents short accounts on selected molecules from the Protein Data Bank...

This feature provides an easy introduction to the RCSB PDB for all types of users, but especially for teachers and students.

source

"Edited (12.24.2019)"

In mammals there're 13 isoforms of this molecule expressed, and in plants there're up to 35 isoforms.

It's involved in the bidirectional transfer of water and small solutes (glycerol, urea, ammonia) through the cell membranes [3]

"Edited (12.26.2019)"

Molecule of this family of proteins is responsible for reabsorbtion of 90% of the 180 liters of water filtered by our kidneys.
The first member (initially known as CHIP28) of this family was discovered in 1992 [4]

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Rules

This contest lasts for 6 days.

Leave your guess (1 guess only) in the comments section of the post.

Don’t edit your comment and don’t provide any evidence that your answer is correct.

I’ll provide the answer in the comments section of the next post on the 7th day of the week’s stage.

The first user with correct answer is the winner.

Some of the clues have already been provided in the post.

Additional clues will be given in 2 days (on Monday, December 23, 2019, 20:00 ± 2 minutes UTC) (I’ll update this post).

And the rest of the clues will be provided in 2 more days (on Wednesday, December 25, 2019, 20:00 ± 2 minutes UTC) (I’ll update this post).

The reason is that some people might need less information to make conclusions that the others.

Additional clues will be added at the end of the "Riddle" section before the "Rules" section with "Edited" label.

The winner will be announced on Friday, December 27, 2019, 20:00 ± 2 minutes UTC in the comments section of the next post. Plus I’ll publish a detailed review of the riddle after a while.

I’ll transfer the tokens (STEM + TMN) (if the winner provides me his/her NEO-address) to the winner on that day (December 27) and add the transaction ID in the comments section.

I’m planning to run this contest every week.
So, you should expect to see the 4th week’s riddle for December on Saturday, December 28, 2019, 20:00 ± 2 minutes UTC.

References

I’ll add all the references for this post later, because most of them contain the name of the molecule.
That would be a spoiler.
I’ll add them after a while.

"Edited"

1. Verkman AS. Aquaporins at a glance. J Cell Sci. 2011 Jul 1;124(Pt 13):2107-12. doi: 10.1242/jcs.079467. Review. PubMed PMID: 21670197.

2. Graca Soveral, Soren Nielsen, Angela Casini. Aquaporins in Health and Disease. New Molecular Targets for Drug Discovery. Inbunden Engelska, 2015

3. Prof. Dr. Eric Beitz. Handbook of Experimental Pharmacology. Aquaporins, 2009. Springer-Verlag Berlin and Heidelberg GmbH & Co. K

4. Dr. Per Kjellbom. Basel, ”Structure and Function of Aquaporins”, 2006.

Important

This contest is the work in progress.
A lot can be changed in the future.
Any recommendations/suggestions are very welcome.
If you have any questions, feel free to ask them in the comments section.

All images (without the license specified) are used under the doctrine known in USA as "Fair Use" (similar doctrines are used in other countries). For more information visit the US Gov website