Polarized residues phospholipase

There are also membrane proteins with extended P-chains through the bilayer, and channel proteins with their hydrophilic inner opening must also contain polar amino acid residues within the lipid bilayer. There is also a group of membrane proteins that are covalently bonded to bilayer lipids, including the glycosyl-phosphatidylinositol anchor [6]. These proteins are exposed on the membrane surface via a spacer arm consisting of an oligoglycan, and specific phospholipases can release the protein. 

Figure 5-2. Typical conservation patterns of three protein classes. Residues invariant or conserved in more than 80% ofthe sequences are printed on a black or grey background, respectively. A Mainly nonpolar conservation in the UBA domain, a small protein domain that interacts preferentially with ubiquitin1781. B Invariant polar active site residues in the phospholipase D family1291. C Nearly invariant metal-binding residues in the HtpX/Ste24 family of Zn-containing metalloproteases.

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