Sciencemadness Discussion Board
Not logged in [Login ]
Go To Bottom

Printable Version  
Author: Subject: Proteins with the same primary structure but different functions?
querjek
Hazard to Self
**




Posts: 76
Registered: 26-8-2008
Member Is Offline

Mood: No Mood

[*] posted on 25-7-2011 at 22:11
Proteins with the same primary structure but different functions?


Hey all,

Does anybody out there know of any proteins with the same (or similar) primary structure but different functions? I was thinking about proteins before going to bed last night and this question came up.

Thanks!




it's all about chemistry.
View user's profile View All Posts By User
chemoleo
Biochemicus Energeticus
*******




Posts: 3005
Registered: 23-7-2003
Location: England Germany
Member Is Offline

Mood: crystalline

[*] posted on 26-7-2011 at 12:23


Well a protein with identical sequence (primary structure...) will have identical functions - but it may be context dependent, i.e. it could exert a different function in the nucleus than it does in the cytoplasm of a cell...



Never Stop to Begin, and Never Begin to Stop...
Tolerance is good. But not with the intolerant! (Wilhelm Busch)
View user's profile View All Posts By User
fledarmus
Hazard to Others
***




Posts: 187
Registered: 23-6-2011
Member Is Offline

Mood: No Mood

[*] posted on 26-7-2011 at 13:33


I can think of three possible cases off the top of my head which might be partial answers to your question:

1)There are pleiotropic proteins which have multiple functions depending on when and where they are expressed and what other signalling proteins are present.

2) There are also which dimerize or trimerize before they have any activity, and they may have different functions depending on whether they are homodimers or heterodimers. Homodimers are dimers formed from two identical proteins, heterodimers are dimers formed from two different proteins.

3) And then there are proteins which may have several different modes of post translational modification. Once the protein is expressed, it must usually be modified by other proteins before it can function. For example, some proteins can function either as soluble signalling proteins or as membrane-bound signalling proteins, depending on whether a specific chemical modification is made that localizes the protein to the cell membrane. The two signalling processes may have completely different functions.

There are also some diseases caused by mis-folding of proteins, typically due to absence of the appropriate chaperone proteins, and two proteins with identical primary structure might act very differently in the cells due to different tertiary structure.
View user's profile View All Posts By User

  Go To Top