Journal:Acta Cryst F:S2053230X20000199
From Proteopedia
(Difference between revisions)
| Line 4: | Line 4: | ||
<hr/> | <hr/> | ||
<b>Molecular Tour</b><br> | <b>Molecular Tour</b><br> | ||
| - | Structure of MP-4 from Mucuna pruriens at 2.22 ֳ… resolution | ||
| - | Abha Jain, Amit Kumar, Meha Shikhi, Ashish Kumar, Deepak T. Nair and Dinakar M. Salunke (1) | ||
ג€¢ Intro Para: MP-4 is a protein purified from Mucuna pruriens and it belongs to the Kunitz type of protease inhibitor (KPTI) family. However, biochemical experiments showed that MP-4 is a poor inhibitor of proteases such as trypsin. It has been shown that MP-4 provides protection against snake venom through an indirect antibody based mechanism (2). Previously, MP-4 structure was determined at a lower resolution, and due to lack of availability of the gene sequence, the assignment of residues, especially of the C-terminal region was based primarily on electron density. The present structure is determined at higher resolution and the improved maps enabled better identification of the side chains. Recently, the genome sequence of Mucuna pruriens became available and confirmed the protein sequence derived based on the electron density maps was correct. The present structure reinforces the idea that the polypeptide sequence of proteins purified from source can be determined using electron density maps if the resolution is sufficiently high. | ג€¢ Intro Para: MP-4 is a protein purified from Mucuna pruriens and it belongs to the Kunitz type of protease inhibitor (KPTI) family. However, biochemical experiments showed that MP-4 is a poor inhibitor of proteases such as trypsin. It has been shown that MP-4 provides protection against snake venom through an indirect antibody based mechanism (2). Previously, MP-4 structure was determined at a lower resolution, and due to lack of availability of the gene sequence, the assignment of residues, especially of the C-terminal region was based primarily on electron density. The present structure is determined at higher resolution and the improved maps enabled better identification of the side chains. Recently, the genome sequence of Mucuna pruriens became available and confirmed the protein sequence derived based on the electron density maps was correct. The present structure reinforces the idea that the polypeptide sequence of proteins purified from source can be determined using electron density maps if the resolution is sufficiently high. | ||
| Line 11: | Line 9: | ||
ג€¢ Functional Para: As the name suggests Kunitz type of protease inhibitors (KPTI) are responsible for inhibiting activity of certain proteases like trypsin. To inhibit proteases, the reactive site loop is known to occupy the active site groove of the target enzyme. The reactive site loop (RSL) is critical for its inhibitory activity and it extends from residue 66 to 74 and forms a loop in 6JBP. The residue at the P1 position of the RSL is the principal residue that decides the inhibitory efficiency of protease inhibitor (3, 4). In functional KTPIs, the P1 position is usually occupied by Arg, Lys, Phe, Tyr, Leu or Met but the electron density map clearly shows that the residue at this position is Ile. The presence of Ile at P1 position may be responsible for weak inhibitory activity exhibited by MP-4 (5). | ג€¢ Functional Para: As the name suggests Kunitz type of protease inhibitors (KPTI) are responsible for inhibiting activity of certain proteases like trypsin. To inhibit proteases, the reactive site loop is known to occupy the active site groove of the target enzyme. The reactive site loop (RSL) is critical for its inhibitory activity and it extends from residue 66 to 74 and forms a loop in 6JBP. The residue at the P1 position of the RSL is the principal residue that decides the inhibitory efficiency of protease inhibitor (3, 4). In functional KTPIs, the P1 position is usually occupied by Arg, Lys, Phe, Tyr, Leu or Met but the electron density map clearly shows that the residue at this position is Ile. The presence of Ile at P1 position may be responsible for weak inhibitory activity exhibited by MP-4 (5). | ||
| - | Reference: | ||
| - | + | ||
2. Kumar, A., Gupta, C., Nair, D. T. & Salunke, D. M. (2016). MP-4 contributes to snake venom neutralization by Mucuna pruriens seeds through an indirect antibody-mediated mechanism. J Biol Chem 291, 11373-11384. | 2. Kumar, A., Gupta, C., Nair, D. T. & Salunke, D. M. (2016). MP-4 contributes to snake venom neutralization by Mucuna pruriens seeds through an indirect antibody-mediated mechanism. J Biol Chem 291, 11373-11384. | ||
3. Bode, W., and Huber, R. (2000) Structural basis of the endoproteinase protein inhibitor interaction. Biochim. Biophys. Acta 1477, 241ג€“252. | 3. Bode, W., and Huber, R. (2000) Structural basis of the endoproteinase protein inhibitor interaction. Biochim. Biophys. Acta 1477, 241ג€“252. | ||
Revision as of 07:28, 15 January 2020
| |||||||||||
This page complements a publication in scientific journals and is one of the Proteopedia's Interactive 3D Complement pages. For aditional details please see I3DC.
