Abstract
We present data that hyaluronan (HA) polysaccharides, about 14-86 monosaccharides in length, are capable of accepting only a single heavy chain (HC) from inter-α-inhibitor via transfer by tumor necrosis factor-stimulated gene 6 (TSG-6) and that this transfer is irreversible. We propose that either the sulfate groups (or the sulfation pattern) at the reducing end of the chondroitin sulfate (CS) chain of bikunin, or the core protein itself, enables the bikunin proteoglycan (PG) to accept more than a single HC and permits TSG-6 to transfer these HCs from its relatively small CS chain to HA. To test these hypotheses, we investigated HC transfer to the intact CS chain of the bikunin PG, and to the free chain of bikunin. We observed that both the free CS chain and the intact bikunin PG were only able to accept a single HC from inter-α-inhibitor via transfer by TSG-6 and that HCs could be swapped from the bikunin PG and its free CS chain to HA. Furthermore, a significant portion of the bikunin PG was unable to accept a single heavy chain. We discuss explanations for these observations, including the intracellular assembly of inter-α-inhibitor. In summary, these data demonstrate that the sulfation of the CS chain of bikunin and/or its core protein promote HC transfer by TSG-6 to its relatively short CS chain, although they are insufficient to enable the CS chain of bikunin to accept more than one HC in the absence of other cofactors.
Highlights
The glycosaminoglycan of bikunin is less than 40 monosaccharides in length, but it can reversibly accept two heavy chains (HCs)
A single HC was transferred to the HA molecules 14 – 86 monosaccharides in length (3–16 kDa), as indicated by a single HC band in each lane and the absence of a second band ϳ83 kDa larger that would have been apparent if a second HC had been added
Heavy Chain Swapping from the Free and Intact Chondroitin Sulfate Chains of Bikunin—We investigated whether HCs can be swapped between HA and the bikunin PG or its free chondroitin sulfate (CS) chain
Summary
The glycosaminoglycan of bikunin is less than 40 monosaccharides in length, but it can reversibly accept two heavy chains (HCs). We discuss explanations for these observations, including the intracellular assembly of inter-␣-inhibitor These data demonstrate that the sulfation of the CS chain of bikunin and/or its core protein promote HC transfer by TSG-6 to its relatively short CS chain, they are insufficient to enable the CS chain of bikunin to accept more than one HC in the absence of other cofactors. HC transfer to these HA molecules is an irreversible event from which subsequent swapping of HCs do not occur From these observations, we hypothesized that either the sulfate groups at the reducing terminus of the CS chain of bikunin and/or the bikunin core protein itself enable(s). We performed a series of experiments examining TSG-6-mediated HC transfer to the free CS chain of bikunin and to the intact CS chain on the bikunin PG
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
