Figure - PMC

Skip to main content

An official website of the United States government

Here's how you know

Here's how you know

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

View full-text article in PMC

. 2021 May 7;218(7):e20202699. doi: 10.1084/jem.20202699

Search in PMC
Search in PubMed
View in NLM Catalog
Add to search

© 2021 Cotton et al.

This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms/). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 International license, as described at https://creativecommons.org/licenses/by-nc-sa/4.0/).

PMC Copyright notice

Figure 4. — Remodeling of the CD1a cleft and surface with short- and long-chain SMs. (A) Side view of CD1a–42:2 SM shows the acyl and sphingosine chains lying parallel in the A′ pocket, where the fatty acyl unit encircles an internal structure known as the A′ pole (Moody et al., 2005) formed by F70 and V12, with the position of the unsaturation in the 42:2 SM shown with a cyan arrow. W14 at the bottom of the A′ pocket floor is flipped toward the F′ pocket. (B) In contrast, 36:2 SM is seated 7 Å lower within the CD1a cleft, and its two chains are oriented antiparallel. W14 is bent toward the A′ pocket so that it lies between the acyl chain in the A′ pocket and the sphingosine chain in the F′ pocket. Unlike CD1a–42:2 SM, R76 and R73 stabilize the phosphate group to bend the SM back toward the cleft. The hydrogen bonds and electrostatic interactions are marked with a dashed line. (C) Superimposed top-down views of the CD1a roof for CD1a–42:1 SM and CD1a–42:2 SM complexes, indicating positioning of CD1a F′ portal adjacent residues R73, R76, and E154, in which R76 and the SM head group orient vertically to protrude above the CD1a platform for CD1–42:2 SM. (D) For the CD1a–36:2 SM complex, R76 and the phosphate in the choline group of SM are positioned near the plane of the CD1a platform.