Aquaporins

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A family of integral membrane  proteins discovered by Peter Arge, Aquaporins (AQPs) provide the rapid movement of water molecules across all plasma membrane. These are found in all organisms. The Exocrine glands that produce sweat, saliva, and tears secrete water through aquaporins.
The structure of  AQP1 is determined x-Ray crystallography. 
Aquaporins are tetramer   protein and having 4 subunits.
 Each subunit have Six transmembrane segment . 


Structure of AQP1 



Aquaporin 1
B and E loop selectively filter.
B and E have NPA (Aspargine, Proline,Alanine)
Aspargin involving in forming H2 bond with Water .
Histidine + Aspartate responsible for maintaining the structure of the loop.
Aspartate and Arginine due to the presence of Arginine residue the movement of cations  is inhibited  by Aquaporins. 
Due to Arginine +VE charge repeal +ve charge ions .
As water enter the aquaporin is able to pass aquaporin by forming the bonds with carbonyl groups present in trans membrane segment.
Regulation of Aquaporin depends on the two process. 
(1). By Calcium ions concentration.
(2). Phosphorylation of Serine residue present at or near to N & C terminal of aquaporin. 

For more Details vigit.  
Crest Science Academy 
Aarif Sir
9050321626


Location: Gurugram, Haryana, India

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