References:

• White, Gary W. (2003-11-01). Using glycosaminoglycans for treating equine joint diseases. dvm360. Retrieved on 2017-07-10.

Made using the chemfig package in LaTex

\documentclass[10pt]{article}

\usepackage{chemfig}

\begin{document}
\setdoublesep{0.091 cm}             % Bond Spacing
\setatomsep{25 pt}                % Bond length
\setcrambond{2 pt}{1 pt}{2.5 pt}    % {Bold width}{1pt}{Hash spacing}
\setbondoffset{1.6 pt}              % Margin Width
\setbondstyle{line width=0.6 pt}    % Line width 
\renewcommand*\printatom[1]{\normalsize \ensuremath{\mathsf{#1}}} 

\newcommand\setpolymerdelim[2]{\def\delimleft{#1}\def\delimright{#2}}
\def\makebraces(#1,#2)#3#4#5{%
  \edef\delimhalfdim{\the\dimexpr(#1+#2)/2}%
  \chemmove{
    \node[at=(#4),yshift=(-50 pt),xshift=(5 pt)]
      {$
       \left\delimleft
         \vrule height\delimhalfdim depth\delimhalfdim width0pt
       \right.
      $};
    \node[at=(#5),yshift=(-13 pt),xshift=(-5 pt)]
      {$
        \left.
          \vrule height\delimhalfdim depth\delimhalfdim width0pt
        \right\delimright_{\rlap{#3}}
      $};
  }%
}
\setpolymerdelim[]
\chemfig{
        @{op,.75}-[:-15]O-[:-15]
        -[6,0.7]
        ?<[7](-[2,0.7]OSO_3H)
        -[,,,,line width=2pt](-[6,0.7]OSO_3H)
        >[1](-[2]-[:-15]O-[:-15]-[:280,2]
                    -[,,,,line width=2pt](-[6,0.7,,2]HN-[:-30,.7](=[:270,.7]O)-[:30,.7])
                    >[1](-[2]-[:-15]O-[:-15]@{cl,.25}
                    )
                    -[3]O
                    -[4](-[2,0.7]-[1,0.7]OSO_3H)
                    -[5](-[2,0.7,,4]HSO_3O)
                    <[7]
            )
        -[3]O
        -[4]?(-[2,0.7]COOH)
}
\makebraces(75pt,75pt){$n$}{op}{cl}
\end{document}

This image of a simple structural formula is ineligible for copyright and therefore in the public domain, because it consists entirely of information that is common property and contains no original authorship.