[startingafresh]

Background:
Polyhydroxyalkanoates (PHAs) are the current biopolymers, or biodegradable polymers whose applications for replacing plastics are under research. PHA is produced in different bacteria by fermentation. The enzymes, PHA synthases, use coenzymeA thioester of (R)-hydroxyfatty acids as substrate.

Query:
1. What are (R)-hydroxyfatty acids?
2. What is the structure of "coenzymeA thioester of (R)-hydroxyfatty acids?

Thank you for all your help. Greatly appreciate it. 

[Babcock_Hall]

The R (almost certainly) refers to the stereochemical configuration of the stereogenic carbon bearing the hydroxy group, and the opposite configuration would be S.  Common hydroxylated fatty acids are hydroxylated at the carbon that is beta to the carbonyl portion of the thioester group (I am not saying that no other hydroxylated fatty acids exist).  An educated guess is:  R1-CH(OH)-CH2-C(O)SCoA, where R1 is the rest of the fatty acid chain.

[startingafresh]

Thanks Babcock_Hall. That was really helpful.