  In the full type IIB open superstring setup, we show that there exists a
vertex operator, denoted by $V_L$, whose renormalization reproduces the same
anomalous dimension matrix that was obtained by Minahan and Zarembo (MZ) in
{\em JHEP} {\bf 0303}, 013 (2003). The vertex operator is a gauge singlet, and
has the same SO(6) index structure as the operator used by MZ. To obtain the
SYM anomalous dimensions, one of the key ingredients is the non-abelianization
of the non-linear sigma model action in a D-brane background.
  In {\em Phys.\ Lett.} {\bf B 660}, 583 (2008), it was conjectured that
quantum effects of open strings on a stack of D-branes should generate the
curvature. Even though the conjecture had passed a few consistency checks, the
role of the higher order curvature terms has remain mostly unobserved until
now. By choosing a special form of the non-abelianized counter vertex, $V_G$,
we show that the SYM result is reproduced. We comment on fermionic completion
of $V_L$ and on how the special form of the non-abelian vertex $V_G$ may arise.
