Sandbox Reserved 478: Difference between revisions
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===Hemopexin-like Domain=== | ===Hemopexin-like Domain=== | ||
The <scene name='Sandbox_Reserved_478/Hemopexin/1'>Hemopexin-like Domain</scene> consists of about 210 amino acids and is composed of four Hemopexin modules (I-IV), each representing a blade of the beta-propeller structure. Each blade starts with either the DAA or DAX motif, in which Asp residues direct the central calcium ion through their carbonyl oxygen atom. <ref>J Li, P Brick, MC O'Hare, T Skarzynski, LF Lloyd, VA Curry, IM Clark, HF Bigg, BL Hazleman, TE Cawston, DM Blow, Structure of full-length porcine synovial collagenase reveals a C-terminal domain containing a calcium-linked, four-bladed β-propeller, Structure, Volume 3, Issue 6, June 1995, Pages 541-549</ref> <ref name=" | The <scene name='Sandbox_Reserved_478/Hemopexin/1'>Hemopexin-like Domain</scene> consists of about 210 amino acids and is composed of four Hemopexin modules (I-IV), each representing a blade of the beta-propeller structure. Each blade starts with either the DAA or DAX motif, in which Asp residues direct the central calcium ion through their carbonyl oxygen atom. <ref>J Li, P Brick, MC O'Hare, T Skarzynski, LF Lloyd, VA Curry, IM Clark, HF Bigg, BL Hazleman, TE Cawston, DM Blow, Structure of full-length porcine synovial collagenase reveals a C-terminal domain containing a calcium-linked, four-bladed β-propeller, Structure, Volume 3, Issue 6, June 1995, Pages 541-549</ref> <ref name="lyer" /> Glu310 also provides the fourth coordination thus completing the acidic patch at the entrance of the central, solvent-accessible channel. The side chains of these residues also help to form salt bridges with β-strands and hold the entrance of the central channel inline. | ||
Three molecules of water are held within the center of the central channel and they are not involved in the geometry of the calcium ion at the center of the tunnel. It has been reasoned that the presence of these ions is not related to the stability conditions but rather a consequence of the crystallization methods. | Three molecules of water are held within the center of the central channel and they are not involved in the geometry of the calcium ion at the center of the tunnel. It has been reasoned that the presence of these ions is not related to the stability conditions but rather a consequence of the crystallization methods. | ||