PHA granule-binding protein

It appears that the proteins locating on the in vivo PHA granule surface could be potential affinity tags for protein purification. Among the nonspecific PHA granule-binding protein phasin as a hydrophobic affinity tag appears to be the most attractive because of its richness compared with others. 

You, M., Peng, G., Li, J., Ma, P., Wang, Z., Shu, W., Peng, S., Chen, G., 2011. Chondrogenic differentiation of human bone marrow mesenchymal stem cells on polyhydroxyalkanoate (PHA) scaffolds coated with PHA granule binding protein PhaP fused with RGD peptide. Biomaterials 32 (9), 2305—2313. 

Fig. 7 PHA granule-binding protein PhaP can be used to achieve protein purification...

Separation of PHASCL and PHAMCL into two separate granules within the same cell often seems to occur if two different PHA synthases with non-overlapping substrate ranges are present in the cell. Obviously, each type of PHA synthase participates separately in the initiation of micelle formation of nascent PHA granules, because only PHA molecules of similar structure, which remain bound to the PHA synthase protein, can contribute to the formation of a micelle. When the granules become larger, further PHA synthase molecules can only bind to the surface of the granules if they represent the same type of PHA synthase. 

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