Understanding through Discussion


Welcome! You are not logged in. [ Login ]
EvC Forum active members: 64 (9057 total)
61 online now:
jar, nwr, Tanypteryx, Theodoric, vimesey, xongsmith (6 members, 55 visitors)
Newest Member: drlove
Post Volume: Total: 889,819 Year: 931/6,534 Month: 931/682 Week: 166/445 Day: 11/48 Hour: 2/0


Thread  Details

Email This Thread
Newer Topic | Older Topic
  
Author Topic:   Deep Homology and Front-loading
Dr Jack
Member (Idle past 1219 days)
Posts: 3507
From: Leicester, England
Joined: 07-14-2003


(1)
Message 69 of 172 (666175)
06-23-2012 8:53 AM
Reply to: Message 67 by Genomicus
06-22-2012 10:39 PM


Re: The Ubiquitin Story
Precisely because without putting a protein that is structurally similar to ubiquitin in the first genomes, you'd have to depend on the blind watchmaker to tinker around with the existing folds, and "just happen" to come up with a protein that is structurally similar to ubiquitin (and also happens to have the necessary sulfur chemistry).

What makes you think either the sulphur chemistry or the protein fold is necessary?

Ubiquitin is a signalling molecule that interact with other proteins. I'm not aware of any reason to think that it isn't arbitrary which features of Ubiquitin are required for it to function; all it needs is the correct "lock and key" interaction with the various other proteins it interacts with.

Edited by Mr Jack, : Missed a not


This message is a reply to:
 Message 67 by Genomicus, posted 06-22-2012 10:39 PM Genomicus has not yet responded

Replies to this message:
 Message 70 by Dr Adequate, posted 06-23-2012 9:49 PM Dr Jack has acknowledged this reply

  
Dr Jack
Member (Idle past 1219 days)
Posts: 3507
From: Leicester, England
Joined: 07-14-2003


Message 126 of 172 (666480)
06-27-2012 4:58 PM
Reply to: Message 109 by Genomicus
06-27-2012 1:10 PM


Ubiquitin is not special
The universal distribution of ubiquitin among eukaryotes strongly implies that it is necessary for eukaryotic existence, does it not?

It implies that our Eukaryotes require it, yes, but it doesn't imply that life like a Eukaryote requires it. There's no reason to think that we couldn't engineer a Eukaryote so that it used a different molecule in place of ubiquitin, it'd just need every protein that interacts with it to be re-worked - which is why evolution can't do it.

Ubiquitin is a signalling molecule, not an enzyme, it's functionality lies in its interaction with other proteins, not it anything inherent to its structure (well, it needs to be small, easily synthesized and capable of being combined into chains but that leaves literally thousands of possibilities).


This message is a reply to:
 Message 109 by Genomicus, posted 06-27-2012 1:10 PM Genomicus has not yet responded

  
Newer Topic | Older Topic
Jump to:


Copyright 2001-2018 by EvC Forum, All Rights Reserved

™ Version 4.0 Beta
Innovative software from Qwixotic © 2022