Comparison between Haemoglobin and Leghaemoglobin?

[Incendia]

I recently learned of a thing called Leghaemoglobin...How does it compare with Haemoglobin?

 

Leghaemoglobin <Wikipedia explaination>: http://en.wikipedia.org/wiki/Leghemoglobin

[CharonY]

Compare in terms of what? Functional groups are similar, though there are significant sequence differences.

[Incendia]

What are their differences? Is one more efficient than the other? Do they produce different products?

[CharonY]

None of them produce anything. Both are involved in gas exchange, though the main function in plants is the delivery of oxygen and CO2 transport probably does not play much of a role. The reason is that leghemoglobin is necessary to deliver oxygen to symbiotic bacteria. However, the bacteria are there to fix nitrogen and they can only do it at low oxygen concentrations. So the leghemoglobin has a very strong binding constant (higher than hemoglobin) in order to ensure an extremely low amount of free oxygen, but still ensure delivery to the bacteria.

Other than that the functional groups are essentially the same, but the overall protein structure is different (both on the sequence and somewhat on the structure level). Both belong to the same protein family, though.

[Incendia]

So the only differences are how how they are structured, sequenced and the fact leghaemoglobin is more efficient at attaching to oxygen.

 

Would it be possible to replace normal haemoglobin with leghaemoglobin?

What would be the disadvantages/advantages of having leghaemoglobin instead of haemoglobin?

[Incendia]

Bump...Please answer my questions...

[cypress]

So the only differences are how how they are structured, sequenced and the fact leghaemoglobin is more efficient at attaching to oxygen.

 

Would it be possible to replace normal haemoglobin with leghaemoglobin?

 

Not it would not, since oxygen transport affinity involves many many coordinated systems that would likewise require replacement.

 

What would be the disadvantages/advantages of having leghaemoglobin instead of haemoglobin?

 

The obvious disadvantage would be that it would not function correctly, for the reason mentioned above.

[Incendia]

Haemoglobin does not require any system to attach to O, CO or CO₂.

I am asking you to compare the two substances. Can you please just do that. The other systems are irrelevant... just pretend the work anyway.

Edited November 27, 2010 by ProcuratorIncendia