In this video, we're going to talk about drawing sphingomyelins. So, drawing sphingomyelin requires recalling the structures of sphingosine and the fatty acids involved. Now, here it says, draw the structure of a sphingomyelin that contains oleic acid. Remember, oleic acid represents an unsaturated fatty acid. Its standard notation or shorthand notation is 18:1. Meaning that we have an 18 carbon fatty acid chain, 1 means we have 1 pi bond, and with these unsaturated fatty acids with 1 pi bond, it's typically at carbon number 9 where we first see it.
Now, come down here, we're going to say step 1 is to draw the sphingosine backbone with a phosphate group at carbon number 1. So here goes carbon number 1 and there's a phosphate group there. We're going to say instead of an NH2 group at carbon number 2, we're going to write only NH. So here there's going to be an NH group right here. And that's because we're going to attach something to that NH group.
Step 2, we're going to extend the phosphate at carbon number 1 with the choline head group. Remember, we're not saying choline, but co-choline head group. So, in choline, we have an ethyl group attached to the oxygen, and then we have nitrogen. Choline is CH. Nitrogen is connected to CH3, 3 of them. Because it's making 4 bonds, it's positively charged.
Coming down to step 3, we're going to draw the fatty acyl group, so the fatty acid without the OH, from the NH group at carbon number 2. So here goes our amide linkage or amide bond that's going to be formed. So, remember, oleic acid is an unsaturated fatty acid. Its standard or shorthand notation is 18:1. So we have 18 carbons, so we have 2, 4, 6, 8, 10, 12, 14, 16, 18, just to be sure. This would be the structure of our sphingomyelin based on the information given to us within the example question. We have our amide bond on Carbon number 2 in terms of its NH group. We have our Phosphate group, as well as the Choline head group on carbon number 1. And of course, on carbon number 3, we have our 15 carbon chain that's also containing a trans double bond.
Alright, so this would be our final answer.
