G proteins are so-called because they bind the guanine nucleotides GDP and GTP. They are heterotrimers (i.e., made of three different subunits) associated with. the inner surface of the plasma membrane and. transmembrane receptors of hormones, etc. These are called G protein-coupled receptors (GPCRs).
Apply the metal paint to the mailbox in slow and even sections. Be sure to cover every inch of the metal mailbox including the door, hanging lip and the back. When this layer is dry remove the tape from the mailbox flag.
The primer wore off and the doors strarted rusting badly. So this past weekend I sanded and painted them using some Rustoleum paint (which is great for metal). The color I chose was Hunter Green with a satin finish. You can barely see it but here is where I can see bulkhead doors in the photo. You can see the bulkhead doors in this photo from when we bought the house. Up close, the doors looked very much like this. I had this new set of steel doors installed a few years ago but forgot to paint them. They were only primed.