Myoglobin
Group 4- DAH
Manalo, Paul
Manggahas, Luis
Manio, Love Joy
Masigan, Stephanie Kyra
Mendiola, Roxanne
Mendoza, Jullienda
August 2014
I. Structure
Myoglobin is almost similar in structures with hemoglobin except on the heme groups attached to it and to the presence of amino acids. Myoglobin only seems like a quarter of hemoglobin. Myoglobin has a molecular weight of 18, 000. It has a component of a single polypeptide chain folded into 8 α- helical structure, 153 amino acids and one heme group attached at the crevice of the molecule. It also contains iron protoporphyrin 9 as its prosthetic group.
The single polypeptide chain, which is folded into 8 α- helical structure, is assigned a letter for each fold. The letters A-H is used to designate the folds in the chain and the spaces between each fold (interhelical regions) are named using the combined letters of the folds between it (example: space between folds A and B is termed as AB).
The heme group is square planar and has 4 pyrrole rings attached to Fe (II) at the center by four α- methylene bridges. It is attached to the polypeptide chain thru the proximal Histidine and the distal Histidine. The proximal histidine or His F8 is attached directly to Fe (II) while the distal Histidine or His E7 has oxygen in between it and Fe (II). His E7 stabilizes the oxygen binding into the molecule.
Myoglobin has on its surfaces polar residues and on its interior nonpolar residues (e.g. Leu, Val, Phe, Met) with the exception of two residues. These are the His F8 and His E7 which has the inverse of the characteristics stated above.
Hydrogen bonding in polypeptide backbone stabilizes the α- helical regions; amino acid side chains are also involved in hydrogen bonds.
II. Biological Importance
Since it is in the family of globins, whose main function is to bind with other molecules, myoglobin also binds with a single type of molecule which is oxygen. Its main function is
Manalo, Paul
Manggahas, Luis
Manio, Love Joy
Masigan, Stephanie Kyra
Mendiola, Roxanne
Mendoza, Jullienda
August 2014
I. Structure
Myoglobin is almost similar in structures with hemoglobin except on the heme groups attached to it and to the presence of amino acids. Myoglobin only seems like a quarter of hemoglobin. Myoglobin has a molecular weight of 18, 000. It has a component of a single polypeptide chain folded into 8 α- helical structure, 153 amino acids and one heme group attached at the crevice of the molecule. It also contains iron protoporphyrin 9 as its prosthetic group.
The single polypeptide chain, which is folded into 8 α- helical structure, is assigned a letter for each fold. The letters A-H is used to designate the folds in the chain and the spaces between each fold (interhelical regions) are named using the combined letters of the folds between it (example: space between folds A and B is termed as AB).
The heme group is square planar and has 4 pyrrole rings attached to Fe (II) at the center by four α- methylene bridges. It is attached to the polypeptide chain thru the proximal Histidine and the distal Histidine. The proximal histidine or His F8 is attached directly to Fe (II) while the distal Histidine or His E7 has oxygen in between it and Fe (II). His E7 stabilizes the oxygen binding into the molecule.
Myoglobin has on its surfaces polar residues and on its interior nonpolar residues (e.g. Leu, Val, Phe, Met) with the exception of two residues. These are the His F8 and His E7 which has the inverse of the characteristics stated above.
Hydrogen bonding in polypeptide backbone stabilizes the α- helical regions; amino acid side chains are also involved in hydrogen bonds.
II. Biological Importance
Since it is in the family of globins, whose main function is to bind with other molecules, myoglobin also binds with a single type of molecule which is oxygen. Its main function is